Frances Tiafoe serves to Adrian Mannarino, of France, during the first round of the U.S. Open tennis tournament, Tuesday, Aug. 28, 2018, in New York. (AP Photo/Frank Franklin II)

NEW YORK — After disappointment at Wimbledon, Frances Tiafoe vowed to learn.

The 20-year-old from Maryland had a spot in the fourth round all but clinched at the All-England Lawn Club back in July before he seized up and lost a crushing five-set match to Karen Khachanov in the third round at Wimbledon, the first time he had advanced that deep. Tiafoe later blamed the stunning loss on stomach pains, nerves and an immense mishandling of an important moment — something he promised he would never forget.

The unseeded American handled the moment just fine Tuesday night at the U.S. Open when he finally broke through for his first main-draw win at Billie Jean King National Tennis Center. He upset No. 29 seed Adrian Mannarino of France, 6-1, 6-4, 4-6, 6-4, in front of a raucous crowd on Grandstand that made it sound like Tiafoe brought all of College Park — where he learned the game as a child — with him.

“Unbelievable. I’ve had a ton of heartbreakers here at the Open, and it’s nice to finally get over the line,” Tiafoe said on court after a few healthy yelps of joy directed at the crowd. “I’m definitely trying to make something happen this year. I’m having a good year, and there’s no better place to do it than New York.”

To be fair, Tiafoe’s breakthrough in Queens may have happened sooner if not for tough draws in his three previous tournaments. As a teenager, he played Victor Troicki in the first round in 2015, John Isner in 2016 and had a ravenous crowd on edge at Arthur Ashe Stadium last year when he pushed Roger Federer to five sets.

Against Mannarino, he showed the power and shot-making that nudged him into the top 40 for the first time this year and earned him his first ATP Tour title in February. Tiafoe advances to face another player on the rise in Australia’s Alex de Minaur in the second round.

They will be joined by fellow “next-gen” players Stefanos Tsitsipas of Greece, American Taylor Fritz and Canadian Denis Shapovalov, all of whom play their second-round matches Wednesday.

Federer rolls through 

Tiafoe and his peers’ youth will be well balanced by the presence of Andy Murray, Rafael Nadal, Novak Djokovic and Roger Federer in the second round. Both Djokovic and Federer won Tuesday, with Federer dismissing 22-year-old Yoshihito Nishioka of Japan 6-2, 6-2, 6-4 in Arthur Ashe Stadium to kick off the night session. It has been 10 years since the Swiss superstar last won in Flushing Meadows.

If he lifts his sixth U.S. Open trophy in September, the 37-year-old would be the tournament’s oldest winner in the Open Era. He is 18-0 in opening-round matches.

On the women’s side, a handful of top seeds advanced without drama the day after top seed and No. 1 player in the world Simona Halep was upset in the first round. Fourth-seeded Angelique Kerber, the reigning Wimbledon champion, advanced past Margarita Garsparyan, 7-6 (9-7), 6-3, to play Johanna Larsson in the second round; fifth-seeded Petra Kvitova beat Yanina Wickmayer, 6-1, 6-4, and plays Yafan Wang next; and second seed and reigning Australian Open champion Caroline Wozniacki defeated former U.S. Open champion Sam Stosur, 6-3, 6-2. Wozniacki faces Lesia Tsurenko next.

Fourteenth-seeded Madison Keys, a finalist in New York last year, closed out the night session on Arthur Ashe with a 6-4, 6-4 win over Pauline Parmentier. She moves on to face her fellow American Bernarda Pera next.

More from the U.S. Open:

Simona Halep makes history as the first top seed to lose in first round

Scratch that: Serena Williams downplays French Open catsuit ban

Serena Williams’s path opens up after Halep upset