Brazil’s Joao Fonseca, by far the youngest and perhaps the least heralded competitor, won the MGM Slam exhibition tennis tournament on Sunday at T-Mobile Arena in Las Vegas.

The event featured eight professional men’s players, including the 19-year-old Fonseca, vying for a $1 million prize pool in a unique, single-elimination format. The first and second rounds were 10-point tiebreakers, and the final was best-of-three.

Fonseca, ranked No. 35 in the world, defeated American Reilly Opelka 10-6, 7-10, 10-5 for the $300,000 first prize.

“I think I have a pretty good mentality,” Fonseca said of dealing with the format, per The Sporting Tribune. “I try to focus my routine and concentrate on each shot. You can’t adjust much. You just go play and focus on that.”

Opelka, 28, is No. 68 in the world. He collected $200,000 for his second-place finish.

World No. 7 Taylor Fritz, the event’s highest-ranked player, defeated fellow American Tommy Paul 10-3 and Opelka knocked out Norway’s Casper Ruud 10-8 in first-round matches. Fonseca eliminated the oldest player, 39-year-old Frenchman Gael Monfils 10-6, and Kazakhstan’s Alexander Bublik, No. 10 in the world, ousted Australia’s Nick Kyrgios 10-8.

Opelka got past Fritz 10-6, and Fonseca crushed Bublik 10-3 in the other semifinal.

–Field Level Media