Justin Thomas credits caddie ‘Bones’ Mackay for US PGA comeback win | Ewan Murray

It remains unclear whether Phil Mickelson will emerge from exile when Greg Norman and his Saudi Arabian circus rumbles into Hertfordshire next month. Mickelson presumably has enough on his mind without contemplating the bitter irony of events at Southern Hills on Sunday. Nonetheless, to others it was striking that as Mickelson – the defending champion – sat at home in San Diego, a man once key to his success was instrumental in Justin Thomas claiming a second US PGA Championship.

Relations between Mickelson and Jim “Bones” Mackay are understood to be non-existent despite 25 years of professional association. Mackay was on the bag as Mickelson won five of his six major championships. Having stepped back from bag‑carrying duties and while working in television, Mackay decided privately that the only player for whom he would return to the game was Thomas. The call arrived last September; eight months on, Thomas has doubled his tally of major victories. “I think he has more shots than anyone on tour,” Mackay says of his employer.

The admiration is mutual. Golfers can sometimes be reluctant to share credit at their highest moments. Not Thomas, who spoke of the heavy influence Mackay had in what was ultimately a playoff success over Will Zalatoris. Caddie and player had a heart to heart after Thomas shot 74 in the third 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 played pretty well for shooting four over and I felt like I’d played terrible. And he was just like: ‘Dude, you’ve got to stop being so hard on yourself. You’re in contention every single week we’re playing.’

“I’ve had a lot of chances to win tournaments and 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 kind of let stuff happen, and everything is trending in the right direction. So just keep staying positive so that good stuff can happen.

“I left in an awesome frame of mind. I think I was the last player to leave. It was so peaceful. It was almost kind of eerie how beautiful it was outside and there’s not very many times after shooting four over on a Saturday of a major I left in as good a frame of mind as I did.”

There was even adversity in round four. Thomas admitted he shanked his tee shot at the par‑three 6th, with the resultant bogey arguably the finest he has ever made.

The 29‑year‑old’s strength of character was emphasised by the scoreboard. Of the top 40 players on it, nobody bettered Thomas’s 67. Only Tommy Fleetwood, who by his own admission did not believe he had a legitimate chance of winning the Wanamaker Trophy, matched it.

Thomas was among those to have sympathy for Mito Pereira, the Chilean who held a one-stroke lead on the final tee of regulation play. Pereira’s cruel double bogey meant he did not even qualify for the playoff but his upbeat, candid performance in front of the cameras thereafter earned him a lot of new fans. Pereira also has the consolation of jumping inside the world’s top 50, from an earlier position of 100th. “You want to win a golf tournament,” Thomas says. “You don’t want someone to lose it.

“Not exactly like that, but I have had times in my career when I feel like I’ve let a tournament get away. And I mean, it’s brutal. It’s not fun. But at the same time if you’re able to channel that, look back at it later or whenever the time is having calmed down and when reflecting, he’ll be able to learn from it and be better from it.

“I know that down the road, whether it’s this year or years to come, if he’s standing on 18 with a one-shot lead in a major, he’s going to feel more comfortable because he’s going to draw on this experience. He played unbelievable golf this week. There’s no reason to hang his head.”

Zalatoris insisted he is “close and super motivated” as he pursues a first main tour win. The good news is he will have an opportunity in three weeks’ time, as the US Open lands in Boston. Thomas will arrive there seeking to join his close friend Jordan Spieth on three major titles. In Mackay, he has a vital ally.