The chants rang out over and over again, from the metal bleachers on Court 12 at the Billie Jean King National Tennis Center.

They were sung like they would be at a football stadium in Rio, or Sao Paolo.

“Jo-ao Fonseca, Jo-ao Fonseca, Jo-ao Fonseca!”  

Time and again, the 75 or so Brazilian fans desperate to see their hero make a comeback and snare a championship Saturday yelled his name. They sang other things, too, but the 17-year-old couldn’t always make them out.

He was up against a brutally tough, unflappable foe in 18-year-old American Learner Tien, who was hungry to win his first Slam title in his last junior Slam.

The full-throated exhortations lifted Fonseca up, to a comeback victory that seemed unlikely for much of the match.

Rallying from a set and 0-2 down in the second, and then another 0-2 deficit in the third, Fonseca became the second Brazilian boy to win the US Open Junior championships, defeating Tien 4-6 6-4 6-3.

Fonseca, who drilled 41 winners to 10 for Tien, becomes the first US Open boys' champion from Brazil since Thiago Seyboth Wild in 2018. Tien was trying to become the first American boy to win on home soil since Taylor Fritz in 2015.

“I can't process. It's really amazing,” Fonseca said. “Yesterday I said I had no words to say but I also said the job was not done. Now the job is done.”

The job got done following a five-hour delay to the match thanks to lightning and rain in the New York area, and the extra rest helped both players physically; with all the stoppages on Friday, both players matches ended after 10 p.m. Friday night, and Saturday’s final was scheduled for 2 p.m. Eastern time.

Tien and Fonseca had met once, with Tien winning a three-set quarterfinal at Roland Garros this past June.

Saturday night’s match started even, with each player holding serve to 4-all. But Tien, who fell in the Australian Open final in January and turned pro this summer, broke serve in the ninth game and then served out the set.

And Tien looked to be firmly in control when he grabbed a 2-0 lead in the second. But at 2-1, Fonseca pounced, and broke back, and that seemed to spur the crowd to further noise.

“When I broke him (at) 2-1, I just, like, called the crowd and energy myself to get strength for the third set to win the second set and go for the third set,” Fonseca said. “So that's why I'm happy with myself that I fought to the last point.”

The match stayed close until 5-4 in the second, when Fonseca smacked a backhand winner on break point to claim the set and send his fans into a frenzy.

In the third, Tien again seemed to wrestle control of the match, using an early break to grab a two-game lead. But Fonseca, who claims Gustavo Kuerten as his idol, showed Guga’s fighting spirit and again came back, winning four games in a row to go up 4-2.

“I was, like, I need to think what he's thinking. He was thinking, okay, now the game is tied (at 2-2), and he's playing better. I was playing more aggressively. I was missing more. But I was playing more aggressive. I was more confident and more courage. That's what made the difference.”

Indeed, Fonseca made 62 errors to but 28 from Tien, but that aggressiveness clearly spurred the win.

“I think he got a lot more rhythm in the third set, he got a lot more confidence,” a crestfallen Tien said. “In that four-game stretch (from 2-0 to 2-4), he raised his game a little bit. He takes a lot of big cuts and when you can build confidence in those areas … when he’s in that zone, it’s tough to play against him.”

Finally, leading 5-3, Fonseca served it out, smashing a forehand winner on match point that kissed the baseline. For a second Fonseca and the crowd thought it was out, but once the chair umpire said “Game” the noise swelled to a cacophony.

Roberta Fonseca, Joao’s mother, was sitting courtside with many members of the family.

“He’s a very good tennis player and a very good human being, and that’s what all mothers are looking for,” Roberta Fonseca said. “It was amazing. Incredible. A dream come true, to see something like this. I am very touched and very proud of him.”

Fonseca effusively praised his opponent, saying how much he respected him.

“Well, he's a great guy. I mean, I'm not, like, very close to him but when I talked to him after the match, he was, like, Man, congratulations. You've got courage. You fought. You deserve it. He just told me that. Very nice to hear that.”

In the boys doubles final, Estonia’s Oliver Ojakaar and Sweden’s Max Dahlin rallied from a set down and saved two match points in a third-set super tiebreaker, to defeat Italy’s Federico Bondioli and Austria’s Joel Schwaerzler, 6-3, 3-6, 11-9.

Down 9-7 in the breaker, Ojakaar and Dahlin smacked two forehand winners to stay alive, and then at 9-9, Ojakaar’s body serve forced an error. On their own match point, Dahlin knocked off a forehand volley up the middle to end the championship.

“It feels amazing, because that was a very tough match,” Ojakaar said. “I was a bit shaky at the start, but as the tiebreaker went on the shakiness went away, and we just went for it.”

“It was a sick match to win; we’ve only played 3 tournaments together,” Dahlin said. “He’s a great partner and it’s so special to win a Grand Slam.”