Defending champion Andy Murray saw off Germany's Florian Mayer in straight sets on a steamy New York afternoon to reach the last 16 of the US Open.
The third seed, 26, looked out of sorts in the opening stages but found his form to win 7-6 (7-2) 6-2 6-2.
He moves into the fourth round for the sixth time and will face Uzbekistan's Denis Istomin on Tuesday.