TULSA, Okla. – Jim “Bones” Mackay is no stranger to major championship Sundays.

During a 25-year career caddying for Phil Mickelson, he was on the bag for five major victories and lost even more, but this Sunday at Southern Hills was different.

Mackay began working full-time for Justin Thomas last September, and on Sunday, the duo won its first major championship together at the PGA Championship.

“If I was ever going to caddie again this was the time and, unquestionably, this was the player,” said Mackay, who was previously working as a Golf Channel analyst since he and Mickelson split in 2017. “My wife will tell you the person I said I’d leave [his job as an analyst] for was Justin Thomas. I think he has more shots than anyone on the Tour.”

Mackay had filled in to work for Thomas in five events in 2020, and the relationship appears to have quickly evolved, with Bones stepping in late Saturday following Thomas’ third-round 74 for an impromptu pep talk.

“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,” Thomas echoed what Mackay told him. “Just keep staying positive so that good stuff can happen. I left here in an awesome frame of mind.”

Mickelson was this week’s defending champion but didn’t play the event following critical comments of both the PGA Tour and LIV Golf which forced him into a self-imposed exile.