A 3-foot putt on the second playoff hole made Blades Brown the youngest PGA Tour winner in 95 years.
The 19-year-old closed with a 9-under 63 to beat Ben James at the World Wide Technology Championship.
“It hasn’t set in just yet, I guess, the magnitude of being a PGA Tour winner,” Brown said.
“I just go back to 5-year-old Blades that was watching the TV and watching Tiger Woods and all those great players win major championships, and to think that I’m now in a similar spot with having won a PGA Tour event is mind-blowing.”
Brown decided to turn professional just two years ago, while still a junior in high school.
No-one younger has won since Charles Kocsis, who was 18 when he took the Michigan Open in 1931, an event considered regional in the early years of the PGA.
James had led by four going into the final round at El Cardonal at Diamante, and lost that advantage.
His response showed moxie: he smoked a 285-yard shot into 20 feet on the par-5 18th and made eagle, salvaging a 70 and forcing a playoff.
“Had a feeling that it was going to go in,” James said of his clutch eagle, the only putt he made all day longer than 15 feet.
“Hadn’t really made anything all day. Just had a really good line on it and it was a good putt. Played the best I could.”
The second extra hole settled it, as James missed from 8 feet and Brown holed his 3-footer.
James was the No. 1 player in the PGA Tour University ranking last season.
Brown earned his PGA Tour card this year through a place among the top 20 in Korn Ferry Tour points.
For a sleepy FedEx Cup Fall event on the southern tip of Baja California, it amounted to a tense playoff between two players from the next generation.
Brown's final round had already erased a seven-shot deficit.
The wait tested him further, as he went through two bags of golf balls on the range to see whether his two-shot lead over James would hold.
Then came a return to the par-5 18th for the playoff.
Their approach shots on the first extra hole finished side-by-side, about 3 feet apart, and both narrowly missed eagle chances.
They went back to the 18th tee, where their drives ended up next to each other, and both came up just short of the green.
James watched his pitch nearly drop before it ran out 8 feet.
Brown had hit a similar pitch in regulation to 6 feet for a closing birdie, but this time came up 3 feet short.
James' birdie attempt grazed the right edge, and Brown poured in the winner.
“I’m so obsessed with this game. It tests you in so many ways,” Brown said. “I love golf, all the stuff that goes into it and I can’t wait for what’s next.”
Eight players had been separated by two shots on the back nine.
Brown ran off three straight birdies to join the lead, then left the mistakes to everyone else.
A superb pitch set up a birdie on the final hole that took him to 23-under 265.
That left him one clear of Michael Kim, who made birdie from 12 feet for a 64 playing alongside the Tennessee teen, moments before Brown's putt dropped.
The victory earns Brown a two-year exemption, placing him in the elite Championship Series when the PGA Tour's new model begins in 2028.
It also assures him of a first major appearance at next year's PGA Championship.
For James, it was another setback: five top-five finishes and two runner-up results have come in his 13 starts since he turned professional.
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