Federer advanced to the next round with a 4-6, 6-1, 6-2, 6-4 triumph over his Indian counterpart Monday at Arthur Ashe Stadium in Queens, N.Y. The victory sets up a second-round match against Damir Dzumhur on Wednesday at Flushing Meadows-Corona Park.
"I think trying to forget the first set is never easy I guess in a first round, under the lights. People expect a different result. I expect something else," Federer told reporters. "I just wanted to pick up my game really, start to play better. I was able to do that. That was a relief, going up 3-love in the second set, realizing that it is on my racket."
Federer is looking to win his sixth U.S. Open title. He has won his first-round match in 62 consecutive Grand Slam appearances.
Federer made 19 unforced errors in his first set loss before turning up the heat on Nagal. The 38-year-old fought off three deuces in the first game of the second set before converting his fourth break point in the next game to take the lead in the match. Federer pushed that lead to 5-0 in the second set before clinching the set on an errant Nagal forehand.
Federer dominated the third set before Nagal pushed the fourth set to 2-2. Nagal fought back to within a point of Federer multiple times in the final set, but could not close the gap against the world's No. 3 player.