Johanna Konta has lost the first set by 6-4 to Ana Konjuh. And she's just been broken in the second so it's looking as if it could depend on the doubles.
By the way, in these Fed Cup matches, the higher ranked of the two singles players for each country plays the higher ranked of the opposing country.
This means that GB is promoted to the World Group II playoffs which will take place in April.
GB will face one country in the playoffs. There are 5 rubbers, 4 singles and 1 doubles. The two selected players for the singles (hopefully Johanna Konta and Heather Watson) play each of the opposing country's two selected players.
GB are hoping that they are able to play here.
Great Britain have qualified for the Fed Cup World Group II play-offs following a 2-1 victory over Croatia.
The tie was decided in the final doubles contest where pairing Johanna Konta and Heather Watson beat Ana Konjuh and Darija Jurak 4-6 6-4 6-3.
Earlier, British number two Watson beat Donna Vekic 6-2 6-4 to give GB the lead in Tallinn, Estonia.
But leading Briton Konta lost 6-4 6-3 to Konjuh in the following singles match as the tie went to a decider.
The doubles partnership were broken twice in the opening three games of that match before eventually losing the first set 6-4.
There was cause for concern when Australian Open quarter-finalist Konta needed treatment on her ankle early in the second set. But the world number 10 overcame the problem as the British pair levelled.
The opening four games of the deciding set went against serve before Konta and Watson secured the decisive break en route to victory.
Captain Anne Keothavong's team will now play one of the four losers from the World Group II matches currently under way.
BBC Radio 5 live tennis correspondent Russell Fuller
The first big selection decision of Keothavong's captaincy proved successful, as Konta and Watson recovered from a set down, and twice a break of serve down in the decider, to wrap up the tie.
Laura Robson and Jocelyn Rae were Britain's first choice doubles pair in the group matches in Tallinn, but were asked to make way for the higher ranked singles players.
Britain crave a first home Fed Cup tie for 24 years, but depending on what happens in other ties this weekend, could end up heading to Australia or Chinese Taipei in April.
The draw takes place on Tuesday.
Looking at the Fed Cup results this weekend I think that GB (23) will be facing one of these in April. Current world ranking shown in brackets.
Canada (17)
Kazakhstan (27)
Serbia (24)
Chinese Taipei (16)
Romania (12)
Australia (11)
or Italy (6)
It's likely that it will be one of the last four on that list but if any two of those four played each other in round one for the last two years then it could be one of the others.
They'll be hoping for a home draw.
One of the sponsors of the Fed Cup (BNP Paribas) award a heart award to one player from each section of the Cup. It will be some time before any announcement is made about the award for Group 1 Europe/Africa. Looking at individual performances there seem to be two people in contention - Ivana Jorovic for Serbia who won all 4 of her singles and the 2 doubles she was in and Heather Watson who also won all 4 of her singles and the 1 doubles she was in.
The four seeded countries for the draw which takes place tomorrow are:
Italy (1)
Romania (2)
Australia (3)
Canada (4)
The seeds have been based on the new rankings which are so new that they aren't yet shown on the Fec Cup site. So the rankings I showed in a previous post may well have changed.
GB, Chinese Taipei, Kazakhstan and Serbia are the four other countries in the draw.
The play-offs are one round of rubbers. The winner will be in World Group 2 next February. The loser goes back to the zone Group 1 either Europe/Africa, Americas or Asia/Oceania.
Great Britain has been drawn away against Romania. GB is now ranked 22 in the world and Romania 14. Matches to be played 22-23 April.
Romania's team last weekend were:
Irina-Carmelia Begu (singles ranking 28/ doubles 124)
Monica Niculescu (39/19)
Sorana Cirstea (61/1112)
Patricia Maria Tig (111/201)
And Simona Halep with a ranking of 4 may be involved.
Laura Robson has turned to Maria Sharapova's former hitting partner Didi Kindlmann as she looks for a coach to guide the next stage of her career.
The former British number one, 23, is working with the German on a trial basis before her next tournament in Yokohama in two weeks' time.
Kindlmann spent three years with Sharapova before her positive test for meldonium at the 2016 Australian Open.
He has since coached world number 22 Anastasia Pavlyuchenkova.
Kindlmann, 34, is now a free agent and well known to IMG, who manage both Sharapova and Robson.
Robson had been working with former players Lucie Ahl and Colin Beecher - employed by Junior Tennis Coaching - since June 2016. The decision to end the partnership appears to have been a mutual one.
Robson won the girls' title at Wimbledon at the age of 14, and reached the fourth round of both Wimbledon and the US Open before she turned 20.
She has been as high as 27 in the world rankings but currently sits at 209, having effectively lost two years to a wrist injury which required surgery.
Robson won her first tournament for eight years in Pennsylvania last August and then qualified for the main draw of the US Open.
However, she lost seven matches in a row between September and January and a sustained run of success will be required before she is able to compete regularly on the WTA Tour again.
Heather Watson moved into the second round of the Abierto Mexicano Telcel with a straight sets win over Bethanie Mattek-Sands.
The Briton double-faulted 10 times as she struggled with her serve but was still able to see off her American opponent 7-5 6-3 in Acapulco.
Watson, 24, plays second seed Kristina Mladenovic (ranked 30) of France in round two.
Britain's Heather Watson lost 7-6 (7-4) 6-7 (5-7) 7-5 to France's Kristina Mladenovic in a three-and-a-half hour battle at the Abierto Mexicano Telcel.
The 24-year-old finally succumbed to Mladenovic, ranked 43 places higher in the world rankings at 30th, with her 18th double fault of the match.
A see-sawing match featured 15 breaks of serve, with Watson converting seven of her 14 chances.
Mixed news about Heather Watson today. Due to the withdrawal of Alize Cornet through injury, she has gone straight into the main draw at Indian Wells.
As a direct result of the Monterrey tournament (which she won last year) being moved to April those points have come off and her ranking has crashed to 108. She's still GB's second ranked player as Naomi Broady has also crashed down to 123. That means that both may have to go into the qualifying stages for the French Open as the cut-off date dicating who qualifies into the main draw is April 17th.
Main draw for first round shows that Johanna Konta has a bye into the second round.
Heather Watson's opponent in the first round is Nicole Gibbs who is ranked 94.
And the winner of that will play Johanna Konta in the second. If it's Heather Watson I hope it goes much better for her than the last and only time they were opponents. That was at Barnstaple in 2013 where she had to retire due to illness, possibly due to food poisoning.
Heather Watson set up an all-British second round tie against Johanna Konta by beating American Nicole Gibbs at the BNP Paribas Open at Indian Wells. The Watson-Konta natch is on Friday.
Gibbs took the first set 6-4 before Watson won the next two sets 6-2, including 10 of the final 12 games.
British number one Johanna Konta beat her compatriot Heather Watson 6-4 6-4 to reach the third round of the BNP Paribas Open at Indian Wells.
Konta, ranked 11th to Watson's 108th, struggled for rhythm in the first set but dominated the second to lead 5-1.
Watson served nine double faults before fighting back but Konta came through.
"It was definitely a brilliant experience for both of us as Fed Cup team-mates and I am very happy to have come through it," said Konta, who was playing her first match in a month after a foot injury.
It was the first meeting on the WTA Tour between Britain's two leading women.
Their only previous contest was at a second-tier tournament in Barnstaple in 2013 when Watson retired after losing the first four games.
Watson broke serve first but then gifted the advantage back as she made three double faults in the third game.
With both players making errors, the pair traded serves again before Konta, who received a bye in the first round, struck the decisive blow by winning the ninth game.
She went on to hold her serve to love to take the first set.
Konta won eight points without reply at the start of the second set and looked on course for a quick victory.
Watson, who threw her racquet in frustration after making three more double faults in the sixth game, found herself 5-1 down before she rallied.
Konta served two double faults in the seventh game and won only two points as Watson, 24, won three consecutive games.
But the 11th seed composed herself to seal her place in the next round after 94 minutes.
Great Britain will travel to the Black Sea city of Constanta for their Fed Cup World Group II play-off against Romania.
The home city of Romanian number one Simona Halep will host the tie on outdoor clay on 22-23 April.
Britain are looking to return to the elite level of the competition for the first time since 1993, but will go into the tie as heavy underdogs.
Halep, the world number four, has already said she will play in the tie.
Romania have four other players in the top 100.
GB captain Anne Keothavong's team kept their promotion hopes alive last month with a 2-1 win over Croatia. and while she will hope to call on Johanna Konta, the world number 11 is not at her best on clay.
British number two Heather Watson is currently ranked 108 but has a strong Fed Cup record with 25 wins and only seven losses.
It is the third time Britain have reached the World Group II play-offs in the past six years, with the team then captained by Judy Murray losing to Sweden and Argentina in 2012 and 2013 respectively.
British number one Johanna Konta is out of the BNP Paribas Open in Indian Wells with a 6-3 3-6 6-7 (1-7) third-round defeat by France's Caroline Garcia.
Konta, seeded 11th, broke Garcia in the fourth game but the 21st seed levelled the match and dominated the third-set tie-break, winning it 7-1.
Garcia, who was once described by Andy Murray as a future world number one, showed impressive resilience to recover from a set down against Konta and sealed her win and a place in the last 16 with a powerful cross-court backhand.
The Miami Open starts today with the qualifying rounds. In the first of two rounds, Naomi Broady is drawn against Marina Erakovic. Katie Swann is drawn against Risa Ozaki.
Heather Watson has gone straight into the main draw as it was based on the rankings before hers tumbled. She's drawn against one of the qualifiers. Whoever wins will be against Kristina Mladenovic (ranked 26).
Johanna Konta gets a bye into the second round where she will be against the winner of the match between Alize Cornet and another qualifier.
British number three Naomi Broady went down 7-5 6-4 to New Zealander Marina Erakovic in the first qualifying round of the Miami Open.
Teenager Katie Swan, the world number 338, was beaten 6-3 6-3 by a player ranked more than 250 places above her, Risa Ozaki of Japan.
British number one Johanna Konta battled her way past Aliaksandra Sasnovich in three sets in the second round of the Miami Open.
Konta won the first set but, despite being 4-2 up in the second, lost it on a tie-break before coming through 6-2 6-7 (7-5) 6-4 against the Belarussian.
The 25-year-old, ranked 11th in the world, will now play France's Pauline Parmentier, the world number 57.
Britain's Johanna Konta rediscovered her best form as she thrashed Pauline Parmentier of France in straight sets to reach round four at the Miami Open.
Konta, seeded 10th, took charge from midway through the first set to win 6-4 6-0 in 63 minutes.
She next faces Lara Arruabarrena in the last 16 after the Spaniard upset eighth seed Madison Keys 7-5 7-5.
British number one Johanna Konta eased into the quarter-finals of the Miami Open with a 7-5 6-1 victory over Lara Arruabarrena.
Konta was given a testing time in the opening set by the Spaniard, who had won only one match this year prior to the tournament.
But 10th seed Konta's serving was key and she broke Arruabarrena at 6-5 up before going on to dominate.
Konta will now play third seed Simona Halep in the last eight.
Romanian Halep saved a match point before beating Australian Sam Stosur 4-6 7-5 6-2.
"I felt I played myself more into the match a bit more," said Konta, who is into the quarter-finals in Miami for the second successive year.
"As the match went on, I felt clearer and clearer on how I wanted to play and what I wanted to do out there from my perspective.
"I'm quite happy I was able to execute that reasonably well, and also make it tough for her to stay in that match with the level that she was playing at."
British number one Johanna Konta produced a superb battling display to reach the Miami Open semi-finals with victory over Romania's Simona Halep.
Tenth seed Konta gave up the only break of the first set but hit back to race into a 3-0 lead early in the second.
Third seed Halep recovered to force a tie-break but Konta dug deep to take it to a decider, which she won at a canter en route to a 3-6 7-6 (9-7) 6-2 win.
Konta now faces Venus Williams, who defeated Angelique Kerber 7-5 6-3.
The other semi-final will be between Caroline Wozniacki and Karolina Pliskova.
Halep, who saved a match point in her win over Sam Stosur in the previous round, edged an even first set thanks to a lone break of the Konta serve, but struggled at the start of the second as Konta took control.
The Briton was just a point away from opening a 4-0 lead but that was the cue for Halep to push again, claiming a vital hold and breaking in the next to get the set back on service.
"I went up to a 3-0 lead and had chances to go 4-0 up, but she's an incredible player and I knew it wouldn't be over until we shook hands," said Konta.
An unpredictable second set was decided in Konta's favour after a scrappy tie-break, after which a clearly rattled Halep was unable to find her rhythm as Konta eased away to victory in two and a half hours.
"I'm really happy to have come through and am looking forward to the next round," added Konta. "It's going to be a tough one."
Johanna Konta defeated seven-time Grand Slam champion Venus Williams 6-4 7-5 to become the first British woman to reach the Miami Open final.
The 25-year-old will face world number 14 Dane Caroline Wozniacki, who overcame Czech second seed Karolina Pliskova 5-7 6-1 6-1.
Konta said: "Caroline's one of the best athletes on tour, so I know I am going to be running for a lot of balls.
"I'm looking forward to it, it is going to be a battle and I will try my best."
Konta broke Williams twice in the first set as she moved into a 3-0 lead, before the 36-year-old American salvaged one of those breaks.
Williams struggled with her first serve and saved five break points early in the second set before breaking Konta to take a 3-1 lead.
But the British number one battled back to break Williams on three occasions on her way to sealing victory shortly after midnight local time.
Konta will reach a career-high world number seven ranking if she lifts the trophy on Saturday.
Johanna Konta took the biggest title of her career with victory over Caroline Wozniacki as she became the first British woman to win the Miami Open.
The 25-year-old British number one overpowered her Danish opponent - a former world number one - 6-4 6-3.
Konta, who in June 2015 was the world number 146, will climb to seventh from 11th in the rankings - her highest yet.
She also takes home ÂĢ940,000 in prize money in claiming what was her third WTA Tour success from a fourth final.
Konta won her first WTA title in July 2016 at the Bank of the West Classic, was defeated in the China Open final in October 2016 and in January triumphed at the Sydney International without dropping a set.
But this was her first success at a higher level - the top 'Premier Mandatory' rung of the WTA Tour.
Having beaten Wozniacki, 26, in their only previous meeting - in straight sets at the third round of this year's Australian Open - Konta was pre-match favourite.
And she held her nerve with a strong all-round performance to edge her opponent in a tight match.
"Thank you so much to the crowd," Konta said.
"You guys were incredible through the whole week. Miami is such an energetic city and you guys really bring that to the court.
"My whole team - thank you so much, we're having a great time working hard and I'm looking forward to continuing to do so."
Wozniacki reached her career high ranking of world number one in October 2010, and victory in Miami would have been her first at this level since Indian Wells in 2011.
But instead she suffered a third final defeat of 2017 - following losses to Elina Svitolina in the Dubai Championships and to Karolina Pliskova in the Qatar Open.
"Jo, you played really well today," Wozniacki said.
"You were the better player and deserved to win. I'm hoping third time lucky [against Konta]. We'll play another time and I'll try my best to win. I was hoping it would be third final lucky this year, but I'll have to go for a fourth."
BBC Sport tennis correspondent Russell Fuller
Only one other player has gathered more ranking points in 2017 than Johanna Konta, but more importantly the new world number seven has now successfully negotiated the perfect dress rehearsal for a Grand Slam.
Six victories over 10 days against the very best in the world in one of the WTA's Big Four tournaments is the perfect stepping stone to Grand Slam success.
Wimbledon should provide Konta with as good an opportunity as the Australian and US Opens - where she has already had so much joy - but now it is time for the clay: a surface on which Konta is still to prove herself.
Britain's Naomi Broady reached the second round of the Monterrey Open in Mexico with victory over American world number 54 Catherine Bellis.
The British number two secured her second WTA Tour win of the year with a 7-6 (9-7) 6-4 victory over Bellis, who is ranked 69 places above her.
Broady served 17 aces in the match, including 11 in the first set as she won a competitive tie-break.
She will face either Hungary's Timea Babos or a qualifier in round two.
Fellow Briton Heather Watson is defending champion and opens her campaign against Serbia's Nina Stojanovic. The tournament was in February last year and the points she won have already fallen out of her ranking points.
Defending champion Heather Watson beat Serbia's Nina Stojanovic in three sets to reach the second round of the Monterrey Open in Mexico.
Watson, 24, fought for two hours and 52 minutes to register a 6-2 6-7 (7-9) 6-4 victory over the world number 126.
The British number three smashed her racquet in frustration after squandering two match points in the second set tie-break.
She will face Russian sixth seed Ekaterina Makarova in the second round.
Watson, currently ranked 125th in the world, led the second set 5-2 before Stojanovic hit back to force a deciding set.
