Justin Thomas, right, celebrates sinking the winning putt at the PGA Championship on Sunday with caddie Jim "Bones" Mackay

Tulsa (United States) (AFP) - Justin Thomas credits a tough talk from caddie Jim “Bones” Mackay with changing his attitude in time to win the PGA Championship, matching the biggest last-round comeback in its history.

Thomas went two-under in a three-hole aggregate playoff Sunday to beat fellow American Will Zalatoris by one stroke at Southern Hills and capture his second major title.

But Thomas recalled how dejected he felt after a third-round 74 Saturday and how much Mackay, the bagman for five major wins in 25 years with Phil Mickelson, turned around his mindset.

“I wouldn’t be standing here if he didn’t give me that talk,” Thomas said of a driving range chat after a woeful round.

“I just needed to let some steam out,” Thomas said. “I didn’t need to bring my frustration and anger home with me. I didn’t need to leave the golf course in a negative frame of mind. I felt like I’d played terrible.

“And he was just like, ‘Dude, you’ve got to be stop being so hard on yourself. You’re in contention every single week we’re playing.

”‘It’s a hard golf course. It’s a major championship. You don’t have to be perfect. Just don’t be hard on yourself. Just keep staying positive so that good stuff can happen.’ I left here in an awesome frame of mind.”

On Sunday, even after falling behind by eight strokes and saying he had written off his chances, Thomas fought back for a dramatic victory.

“Although there might be people ranked higher than me, at least in my eyes, I’m on top of the golfing world right now and I’m very, very proud of that,” Thomas said.

“I’ll let the trophy and the week speak for itself.”

Thomas, who will jump from ninth to fifth in the rankings, won his first major title at the 2017 PGA and had wondered when another might come.

“Five years is a long time,” he said. “I feel like I’ve played just as well as anybody on tour this year. I just haven’t had the trophies to show and I’d fallen in the world ranking.

“It’s easy to start letting some doubt creep in and just, all right, what’s going to happen, when is it going to happen, is it going to happen?”

Thomas matched the greatest last-round victory comeback in PGA Championship history, the seven-stroke rally by John Mahaffey in 1978 at Oakmont.

“It’s very special,” Thomas said. “A lot of self-belief, lot of patience.

“I was walking up 18 in the playoff, and I knew it wasn’t over, but I looked up and I wanted to take it in because you don’t know when and if it’s going to happen again, and it’s such an unbelievable, cool feeling that you just want to enjoy it.”

- Congrats from Tiger -

Tiger Woods, a 15-time major winner and pal of Thomas, tweeted praise a day after withdrawing from the event following his third-worst career major score.

“Big congrats to @JustinThomas34! He kept himself in this championship until the very end and once he got his shot he didn’t look back,” Woods wrote.

Thomas won a PGA crown on the same course where Woods won one in 2007.

“Now I only have like 150 other things to do that he’s done to where he can stop giving me grief,” said Thomas. “So I guess it’s just a stepping stone.”

Thomas applauded Woods’s comeback effort and his making the cut in April’s Masters.

“He made the cut in his second major in a row after being in a gruesome car accident. I don’t think you guys understand how unbelievable that is,” Thomas said. “He’s a freak of nature. It’s mind-blowing the things that he can do with his mind.

“Him making the cut these last two tournaments for some of the conditions he was in last year, it’s absurd. Like beyond absurd.