Top-seeded Jannik Sinner surprisingly dropped his first set of the U.S. Open before rallying for a 2-6, 6-2, 6-1, 6-2 win over Mackenzie McDonald in the first round Tuesday in New York.

McDonald, an American ranked No. 140 in the world, had the home crowd on his side as he broke the Italian’s serve in an opening game that featured five break points. Sinner came back to tie it 2-2 before McDonald rattled off the final four games of the set.

McDonald broke the World No. 1 again in the first game of the second set, but Sinner responded by winning four in a row and took control for the rest of the match.

“I started not in the best way, for sure, but the first match in every tournament is not easy,” Sinner said in his on-court interview. “You have to accept it. He played really, really well at the beginning and I tried to stay there mentally, tried to get into a rhythm. I did that at some point in the second set and then just tried to keep going, so I’m very happy to be in the next round.”

Sinner, who won the Australian Open in January for his first major trophy, is playing his first tournament since news broke that he tested positive for a banned steroid twice in March but avoided suspension.

Sinner hit 12 aces to McDonald’s two, saved 7 of 11 break points and capitalized on his opponent’s 46 unforced errors. This marked Sinner’s first win inside Arthur Ashe Stadium.

“We go day by day. (Wednesday) I have a day off and we will try to get a little bit more rhythm and try to improve for the next match,” Sinner said.

He’ll face an American for the second straight round — 20-year-old Alex Michelsen, who defeated countryman Eliot Spizzirri 6-1, 7-5, 6-3.

Polish No. 7 seed Hubert Hurkacz opened his tournament with a 6-3, 7-6 (4), 7-6 (3) win over Kazakh qualifier Timofey Skatov. He avoided the carnage that befell several other seeded players in first-round action.

No. 11 seed Stefanos Tsitsipas of Greece is already out, as Australia’s Thanasi Kokkinakis beat him 7-6 (5), 4-6, 6-3, 7-5.

“That was incredible … I expected a war,” Kokkinakis said. “It was physical out there. I have a tendency to drag these matches on into real long battles. I just tried to stay focused on every point.”

Also, Jakub Mensik of the Czech Republic swept past No. 19 seed Felix Auger-Aliassime of Canada 6-2, 6-4, 6-2, and Belgium’s David Goffin beat No. 22 seed Alejandro Tabilo of Chile 7-6 (7), 6-1, 7-5.

British 25th seed Jack Draper led 6-3, 6-0, 4-0 when Chinese opponent Zhizhen Zhang retired. No. 30 Matteo Arnaldi of Italy beat American wild card Zachary Svajda in straight sets.

Also winning Tuesday were Nuno Borges of Portugal, Tomas Machac of the Czech Republic, Frenchman Adrian Mannarino, Russia’s Roman Safiullin, Finland’s Otto Virtanen, Australians Tristan Schoolkate and Jordan Thompson and Argentina’s Facundo Diaz Acosta and Mariano Navone.

–Field Level Media