Five-time champion Roger Federer needed five sets to overcome American teenager Frances Tiafoe in the first round of the US Open.
The 36-year-old Swiss won 4-6 6-2 6-1 1-6 6-4 in his first ever match under the Arthur Ashe Stadium roof.
Third seed Federer goes on to face Slovenia’s Blaz Kavcic or Mikhail Youzhny of Russia on Thursday.
Only nine players completed their matches as rain wiped out much of Tuesday’s schedule.
Top seed Rafael Nadal beat Serbia’s Dusan Lajovic 7-6 (8-6) 6-2 6-2, before American 15th seed Madison Keys opened the night session with a 6-3 7-6 (8-6) victory over Belgian Elise Mertens.
They benefited from the stadium-court roof, which was not in place when Federer last played at Flushing Meadows two years ago, a knee injury forcing him out 12 months ago.
A crowd of almost 24,000 packed in to see his return to New York, but 19-year-old Tiafoe ensured they saw a far closer contest than expected.
‘It’s going to give me great confidence’
A slow start, first-serve percentage of 54%, and 56 unforced errors were evidence that Federer was well short of his best, but he was happy to come through after a build-up disrupted by a back injury.
He first felt the problem in the Montreal final three weeks ago, and subsequently pulled out of the Cincinnati Masters.
“I was maybe a bit worried from the beginning with my back issue, but eventually I was able to let go,” said Federer.
“If I felt that my back was going to get worse every match, I probably wouldn’t have played. My hope and belief is that it’s only going to get better.”
The Swiss has yet to lose a Grand Slam match this year, having won his 18th and 19th major titles in Australia and at Wimbledon, while skipping the French Open.
Few expected Tiafoe, the world number 70, to trouble him greatly, but in a match where errors far outstripped winners, amid wild swings of momentum, the teenager ran him close.
Asked how he felt at the end of the match, Federer said: “Extremely well. To get through a five-setter you have to be OK.
“It’s going to give me great confidence in the body and in my game, because preparation was a little bit compromised, so I’m really, really happy with tonight.”