Roger Federer weathers slow start, says he feels 'extremely well'

Federer loves playing in front of New York crowd (2:41)

Roger Federer discusses the emotions of playing at the US Open and credits his opponent, Frances Tiafoe, for his struggles throughout the match. (2:41)

NEW YORK -- They have no idea how long this is going to last, because science says that a 36-year-old with a bad back can't possibly keep doing this. Even his longtime agent could not have foreseen what Roger Federer has done this year. "Never," Tony Godsick said. "He was out for six months [in 2016] and didn't hit a ball."

Two weeks after withdrawing from the Cincinnati Masters because of back pain, Federer was challenged mightily on Tuesday night by 19-year-old American phenom Frances Tiafoe at the US Open. Federer staved off an upset with a 4-6, 6-2, 6-1, 1-6, 6-4 victory in the opening round at Arthur Ashe Stadium.

His path is still clear for a third Grand Slam title this year, which seems unthinkable considering he hadn't won a single one for four seasons before 2017, and because 2016 was so disastrous that he injured his knee drawing a bath for his twin daughters, had surgery for the knee, and struggled with back problems that have plagued him off and on since he was 18 years old.

But this is Federer's year, his renaissance, and the crowd could feel it around midnight, when Federer finally dispatched Tiafoe. Though Federer appeared tentative at times, he said he "was never in pain," although he was worried about how his back would hold up.

"I don't think I had the preparation I was hoping to get," Federer said. "Since Montreal, [the] focus has been more on the back, making sure I can play the tournament rather than being well-prepared. I always knew I was going to come in feeling rusty or not great. I was hoping to start better. I really struggled early on.

"I think Frances connected well. I just really kind of lost my footing sometimes. My eye wasn't working. I was misjudging distance. I think I was also being a bit cautious with my movement. Then in the second set I think it all started to come together."

He injured his back on Aug. 13 in the finals at the Rogers Open, which he lost to Alexander Zverev. Federer pulled out of the Cincinnati Masters the next day. On that final day in Montreal, Federer looked every bit of 36. But for the first eight months of 2017, he has seemed ageless. He won the Australian Open in January, then cruised to the Wimbledon title without even dropping a set. The theory was that his body was rested and fresh after shutting it down for six months in 2016.

The rest during the past two weeks seemed to help Federer on Tuesday. He showed flashes of familiar brilliance in the second and third sets, when he won eight of nine games. But every time it looked as if Federer would take over, Tiafoe stormed back.

Though the teenager came into the night ranked No. 70, he was not an easy first-round matchup. Tiafoe is being described by some as the future of American tennis. Federer has won 19 Grand Slams, one for every year Tiafoe has been alive, but it was clear that the kid had earned Federer's respect. He patted Tiafoe on the shoulder and chest at the end of the match, and told him that he's going to keep getting better and better.

"You're going to have one hell of a future," Federer said he told him. He told Tiafoe that he has had a great year so far.

So has Federer.

It was sort of a strange postmatch scene, the old and the new. Tiafoe showed up for his news conference in a red bucket hat, looking every bit of 19. Several members of the media applauded him as he entered the room.

Tiafoe called Federer the greatest of all time.

Federer left Tuesday night without more worries about his back. He believes it is getting stronger. He felt it as the match, and this unbelievable season, continued on.

"I'm very happy how I'm feeling right now, how I felt coming off the court," Federer said.

"Look, if I enter the tournament, it's because I believe I can play and go deep. I still believe that. I think this will actually give me a lot of confidence."