American qualifier fought off ninth-seeded Pablo Carreno Busta in a pulsating US Open opener.
Defending champion advances to round three when Olga Danilovic withdraws.
"I'm very happy and like proud to be kind of holding the Swiss flag up on the tournaments that Roger and Stan cannot play," says Belinda Bencic.
"I think Stefanos can play well if he doesn't go to the moon and back for a toilet break," says Alexander Zverev.
The Austrian weighs in on the biggest controversy of Day 1
The Scot was ticked off about the Greek's bathroom break after losing in five sets on Day 1.
"As long as I feel good, just maybe hopefully give myself another shot at this tournament next year," said John Isner after his US Open first-round exit.