Roger Federer survived a five-set battle to defeat American teenager Frances Tiafoe and reach the US Open second round on Tuesday, keeping his bid for a record sixth New York title alive.
The 36-year-old Swiss, chasing his third major of the year and 20th of his career, prevailed 4-6, 6-2, 6-1, 1-6, 6-4 to avoid losing in the first round of a Slam for the first time since the 2003 French Open.
The fast and furious duel under the roof of Arthur Ashe Stadium was one of only nine matches to be completed as torrential rain swept 55 matches off Tuesday's schedule.
At times, Federer also looked as if he was about to disappear with the deluge, struggling with a back injury as well as the all-out assault of Tiafoe, the big-hearted 19-year-old son of immigrants from Sierra Leone.
Spain's Rafael Nadal serves to Serbia's Dusan Lajovic during their 2017 US Open first round match, at the USTA Billie Jean King National Tennis Center in New York, on August 29, 2017
But the veteran survived to register his 79th win in New York and set-up a second round match-up with either Russia's Mikhail Youzhny or Blaz Kavcic of Slovenia.
"It was more than a test. We enjoyed it out there, we kept fighting, trying and it was exciting," said Federer, who finished with 17 aces, 41 winners and 56 unforced errors.
"I had a slow start. I was worried about the back injury. In the fifth set, it was a coin toss and it went my way tonight so I am very happy."
"I am feeling extremely well. This will give me great confidence," added Federer, who missed the 2016 tournament with injury and was playing under the $150 million Ashe roof for the first time.
The back problem, which Federer suffered in losing the Montreal final to Alexander Zverev and ruled him out of the Cincinnati tournament, restricted his movement in the opening set.
Naomi Osaka of Japan celebrates defeating Angelique Kerber of Germany in their 2017 US Open first round match, at the USTA Billie Jean King National Tennis Center in New York, on August 29, 2017
World number 70 Tiafoe claimed it on the back of an uncharacteristic 18 unforced errors by the Australian Open and Wimbledon champion.
Federer swept through the next two sets before Tiafoe leveled by storming through a 24-minute fourth set.
In the decider, Federer broke for 3-1 but wasted a match point as he served at 5-3 and was broken by the American.
But Tiafoe's nerve failed him in the 10th game and the match was over when he dumped an off-balance forehand into the net.
The win took Federer's first-round record in New York to 17-0 while world number one Rafael Nadal, a two-time champion in New York, went to 13-0 after the French Open winner claimed a 7-6 (8/6), 6-2, 6-2 win over Serbia's Dusan Lajovic.
- Nadal, Osaka through -
Jelena Ostapenko of Latvia hits a return during her 2017 US Open first round match against Lara Arruabarrena of Spain, at the USTA Billie Jean King National Tennis Center in New York, on August 29, 2017
The 31-year-old Spaniard was critical of the noise inside the Ashe stadium, which was amplified to distracting levels by the roof, which was closed for virtually the whole day.

"I understand it's a show, but under the roof we need to be a little bit more strict about the noise. All the noise stays inside, and this is difficult," said Nadal.

With play on the outside courts trimmed to a mere 90 minutes, it means 87 singles matches will be staged on Wednesday.

Japan's Naomi Osaka was one of just seven women to get through to the second round, aided by playing under the roof.

The world number 46, born in Japan to a Haitian father and Japanese mother, clinched a 6-3, 6-1 win over sixth seed Angelique Kerber, who became the first women's defending champion to lose in the first round since Svetlana Kuznetsova in 2005.

Czech Republic's Karolina Pliskova celebrates after defeating Poland's Magda Linette during their 2017 US Open Women's Singles match at the USTA Billie Jean King National Tennis Center in New York on August 29, 2107
Osaka, who surrendered a 5-1 final-set lead on the same court in losing to Madison Keys in the third round 12 months ago, fired 22 winners as Kerber went tumbling out of the world's top 10 as well as the tournament.
"At 4-1, I was hoping I don't do what I did last year," said the 19-year-old Osaka, who admitted suffering a brief flashback to her tearful loss to Keys.
Kerber is the third top seed to go out in the first round after number two Simona Halep and seventh-seeded Johanna Konta lost on Monday.
- Pliskova, Ostapenko advance -
World number one Karolina Pliskova, the runner-up in 2016, eased past Poland's Magda Linette 6-2, 6-1 on the back of eight aces and 29 winners.
French Open champion Jelena Ostapenko downed Spain's Lara Arruaberrena 6-2, 1-6, 6-1 in a match relocated from Court 17 to Ashe.