The Louisville native sunk a three foot putt to defeat rival Luke List on the first playoff hole at the Honda Classic in Palm Beach, Florida.
But not before taking an unruly fan to task.
As he approached the 16th tee, Thomas heard a fan yell "I hope you hit it in the water."
Upon striking his tee shot, he heard another call: "Get in the bunker!"
"I was like, 'OK, I've had enough,'" Thomas told reporters later. "I just turned around and asked who it was, and he didn't want to say anything, now that I had actually acknowledged him. So he got to leave a couple holes early.
"I don't want to kick someone out just to kick them out. It's just so inappropriate. We're out here trying to win a tournament."
Thomas was tied for the lead at the time and held his nerve to card two pars and a birdie on the final three holes to finish level with List at eight-under-par.
One more birdie on the first playoff hole was enough to seal his sixth tournament win since the start of 2017.
"It just felt great to get it done," Thomas later said.
"I feel very confident in pretty much every part of my game right now.
"I just hit some really, really well-executed shots coming down the stretch. I haven't done that on (holes this difficult) before," he added.
Tiger bites back?
A strong field at PGA National saw Sweden's Alex Noren finish one shot behind Thomas and List while Englishman, Tommy Fleetwood, was a shot further back in fourth.
Tiger Woods also put in a creditable performance, finishing level par for the week.
Fourteen-time major winner Woods has been inhibited by a series of injuries in recent years and has struggled for form.
But his 12th placed finish in Florida marks his best performance at a PGA event since the 2015 Wyndham Open.
"Each and every time out, I'm getting better," Woods said in comments carried by the PGA Tour website Sunday.
"I thought I played well this week, I really did. I had control of it. I didn't play the last few holes well a couple days but ... I'm pleased with the progress I made and I gave myself a chance at it," he added.