Brazilian 18-year-old Thiago Seyboth Wild became the first player from his country to win the US Open boys' title on Sunday, defeating first-time finalist Lorenzo Musetti inside Louis Armstrong Stadium.

Seyboth Wild toppled Italian Musetti, 6-1, 2-6, 6-2, in a high-quality finale, rallying from a break down in the third set to win his first major. The victory comes after the disappointment of losing both the singles and doubles semifinals in Paris four months ago.

"Being in the semifinal of a Grand Slam, it's already a huge thing to be done," he said. "I felt like I want it more because I wasn't satisfied with that semifinal. I was injured during the match, and I was out of practice, out of tennis, for three weeks because I couldn't rise [sic] my arm. I couldn't do anything.

"When I got here this week, I was, like, 'OK, this is it. I gotta do it now.' I just focused on myself and my tennis. I just kept everything simple."

Seyboth Wild won the last five games of the first set to take the opener in just 18 minutes, breaking in the second and third Musetti service games to grab the early advantage.

Musetti, who started slicing his backhand instead of taking full hacks with his Stan Wawrinka-esque one-hander, forced a decider with a pair of breaks at 3-2 and 5-2 in the second set, and he seized his second break point of the third set to take a 2-0 lead.

But Seyboth Wild made the necessary adjustments, and he broke three times in a row in reeling off the final five games to seal the title.

"I had a break point ... at two-all, 30-40. He served second serve wide, and then [I] literally just slapped a ball out of the court," Seyboth Wild said. "That just turned my head upside down. I was, like, 'Why did I do that?' I kept thinking about it for three or four games.

"He got like four or five straight games. He broke my serve three times. I was, like, 'OK, I need to do something to change it.' When I lost my serve in the third set, he was 2-0 up, I was like, 'OK, I will start running, try to do something different.'"

Those tactical changes, plus a visible increase in effort, proved to be the difference in the match. And while Musetti was disappointed with not being able to hang on to his third-set lead, he was happy with the way he played this week in New York.

"I think first set he played so good, he didn't miss one shot," Musetti said. "Only winners, so I couldn't do anything. Then I started to change my game to make him miss, and he started to miss.

"It's OK. It was a great run here, and I'm a little sad, but it's OK. I think he played over his level and over mine. He played so good. All the winners, I couldn't do anything. I'm proud of myself. Now not so much, but when I get home, I'll be proud of me. I think this let me train more and more to get the trophy. I didn't have the feeling that I could play like this. I'm happy to discover it."

September 9, 2018 - 2018 US Open Junior Boy's Doubles Champions Adrian Andreev and Anton Matusevich. (USTA/Pete Staples)
Photo by:  (USTA/Pete Staples)

Silverware was also handed out in the boys' doubles on Sunday, with Anton Matusevich and Adrian Andreev defeating the American duo of Emilio Nava and Axel Nefve, 6-4, 2-6 [10-8].

"It's my first doubles title, so it's a pretty good first title to win," said Matusevich. "We're actually both singles players, so it means a bit, but not like a lot to us. It's good experience, and it's good because it's a Grand Slam. That's the main thing."

Brit Matusevich and Bulgarian Andreev broke in the third game of the match and captured the first set on their first set point after previously saving four break points at 4-3.

The Americans rallied back behind consecutive breaks at 3-2 and 5-2, forcing a 10-point match tiebreak.

Andreev and Matusevich were down 6-5, with the Americans set to serve the next two points, but they responded by capturing those next two points and claiming five of the final seven. On match point, a high Matusevich second serve kicked too high for Nava to return, setting off a celebration between the partners, who only decided to team up two weeks ago when Matusevich messaged Andreev on Instagram. 

"We are fighting for every point, trying our best, and I think that's the most important thing in every sport; it's how much you want to win," Andreev said. "If you fight every point, you have more chances to win the tournament, for sure. But we did not expect to win the tournament."

Nefve thanked his parents and friends for their support, and he thanked Notre Dame University, where he will begin his freshman year next week, two weeks into the semester, for letting him take time off to compete at Flushing Meadows.

Added partner Nava: “It’s a great tournament. First US Open final, it feels amazing."