NEW YORK (AP) Roger Federer regrouped after a fortuitously timed rain delay to move on at the U.S. Open in four sets.
The second-seeded Federer was a game from losing the first set to Marcel Granollers in the third round Sunday when play was stopped because of lightning.
After they returned to the court two hours later, Granollers won the set, but Federer dominated the rest of the way in a 4-6, 6-1, 6-1, 6-1 victory.
Drenched with sweat on a humid night, Federer acknowledged afterward that the break helped him. He started serving better in the final three sets.
''He was doing a lot of things really well,'' Federer said later. ''It was just, for me, going to be one of those things to like weather the storm and see if he could maintain that level of play or not and if I could lift my game up and see how that matched up. I think overall it worked out great at the end.''
The 42nd-ranked Granollers was looking to make the fourth round at the U.S. Open for the second straight year.
Federer next faces 17th-seeded Roberto Bautista Agut of Spain, who beat Adrian Mannarino 7-5, 6-2, 6-3. The 17-time Grand Slam champion has dropped one set through three matches.
''I feel very explosive, quick,'' Federer said.