Roger Federer reacts during the men's singles first round match against Sumit Nagal of India at the 2019 US Open in New York, the United States on Aug. 26, 2019. (Xinhua/Li Muzi)

NEW YORK, Aug. 26 (Xinhua) -- Five-time champion Roger Federer of Switzerland rallied past Indian qualifier Sumit Nagal 4-6, 6-1, 6-2, 6-4 in the opening round of the US Open on Monday.

The Swiss mogul dropped the opening set in 36 minutes, then returned to form and defeated Nagal after battling for two hours and 30 minutes.

"I think trying to forget the first set is never easy in the first round. People expect a different result. I expect something else," Federer said. "I just wanted to pick up my game really, start to play better. I was able to do that. That was a relief."

Roger Federer hits a return during the match. (Xinhua/Li Muzi)

"I wasn't serving consistently enough in the opening set. I was hitting double faults that usually I don't do. Also, I was just hitting too many unforced errors."

"I was able to clear that a little bit. Maybe it's not a bad thing to go through a match like this. It was very similar at Wimbledon when I dropped the first set there as well in the first round. At the end, you look at the last three sets, and they were good. That's encouraging," Federer added.