Latak is the first American to claim the junior singles crown in New York since Taylor Fritz in 2015. The other US winners this century were Andy Roddick (2000) and Jack Sock (2010).
The unseeded home player led the deciding tie-break 7-2 and later 9-6, then had to recover after those leads slipped. He finished the match with a backhand winner and collapsed to the court in celebration.
Latak did not drop a set before the final. He beat sixth seed Ziga Sesko, 10th seed Dimitar Kisimov, fourth seed Keaton Hance and second seed Jamie Mackenzie. In all he eliminated five of the top 10 seeds, including four of the top six, and lost only one set in the tournament.
Miguel, a 17-year-old Brazilian, won the Roland Garros boys’ title earlier this year and had taken a set off an ATP 500 opponent in Rio. He beat Wimbledon junior champion Jordan Lee in the US Open quarter-finals.
“I’m pretty stoked about how today went down,” Latak said. “I just told myself to go for it. I was up most of the breaker in the third set, so dropping those match points honestly wasn’t anything new. I’ve dropped so many this tournament before I closed them out.”
He added that beating the world No. 1 was “mostly mental”.
Harrison and Skupski had already won the men’s doubles title. The men’s singles final between Alexander Zverev and Ben Shelton follows.