Robert MacIntyre captured his maiden PGA Tour win on Sunday when the Scotsman closed with a two-under 68 for a one-stroke victory in Ontario.

The Oban native, playing in his first full season stateside, finished on 16-under 264 at Hamilton Golf and Country Club to hold off a hard charging Ben Griffin (65) as the American closed with three-straight birdies starting from the 15th hole to put pressure on MacIntyre.

The victory was worth 1.692 million U.S. dollars.

"I was rolling it unbelievable all week. Honestly, I didn't seem to miss any putts and at nine and 10, I was like, 'these are getting buried'. I missed 'em and I was like, 'that's fine'," said MacIntyre.

"Then I started getting heckled a bit from the crowd, and I rolled that putt in on 11. I think I let my emotion go a bit too much and I kind of lost the focus. But it was one that I was just - I was getting back at the guys that were heckling me for a few holes."

France's Victor Perez (64) was third at two shots back, a shot ahead of South Korean Tom Kim (64) and World No. 3 Rory McIlroy, a two-time winner of the tournament, who closed with a 64.

MacIntyre, who had his father, Dougie, serving as his caddie in an emergency basis after his regular looper had a wedding commitment, started the day with a four-shot lead and got off to a rough start with a bogey five on the opening hole. He then settled down to make three birdies to make the turn at two-under 33.

The back nine provided more peril for MacIntyre as he carded two birdies and two bogeys to let Griffin get within one shot going into the final hole. With Griffin leaving his second shot in the greenside fringe, MacIntyre made no mistake in his approach from 185-yards out in placing his ball 10 feet from the pin. As Griffin left his birdie putt four-feet short of the hole, MacIntyre two-putted for the win.

"No, I was in a dog fight there," said MacIntyre. "Obviously, Ben (Griffin) made it difficult coming in the stretch. He played well. It's just incredible to do this with my dad on the bag and have my girlfriend here. I'm sure there's a party going on back home in Oban."

Griffin, who had quit competitive golf in 2021 to work for a mortgage broker before returning the following year, got close to his first PGA Tour win with a bogey-free round that included five birdies.

"Yeah, I fought hard," said the 28-year-old North Carolina native. "It felt like there was a lid on the cup for most of the day for me. I hit so many pretty good putts. I wouldn't say like striped putts, but pretty good putts and just kept burning edges - a couple bad putts - but stayed patient."

McIlroy started the day seven strokes back and made a go of it in his bogey-free round that included six birdies, including four over the first six holes, but was never close enough to put pressure on MacIntyre, his teammate on last year's victorious European Ryder Cup squad.

The four-time major winner lamented a poor round on Friday where he shot two-over 72 as the difference in his week.

"My goal was to at least make Bob (MacIntyre) shoot under par. I thought if I could get to 14 (under) he would have to go out and shoot something in the 60s to win, so that was the goal. I came up one short of that," said McIlroy.

As native Hamiltonian Mackenzie Hughes struggled in his final round to an even-par 70 after starting four shots off the lead, Corey Conners finished as the top Canadian in sixth after closing with a five under-65. His round included seven birdies, five of them coming on the back nine, and two bogeys, including one at the 458-yard last.

The Ontario native called it a "huge honor" to finish as the low Canadian at his national championship.

"I wanted to get myself in the mix this week. Definitely felt like my game was trending quite positively the last few weeks that I played," said Conners, a two-time winner on the PGA Tour. "I'm continuing to feel better and better about things. Definitely take lots of confidence from this week."