Rory McIlroy saved his best for last to defend his Canadian Open title on Sunday and could not resist a sly dig at LIV Golf chief executive Greg Norman afterwards.

At the end of a chaotic week for the sport, with the controversial Saudi-backed LIV Golf Invitational Series commencing in competition with the PGA Tour, McIlroy posted his best round of the tournament at St. George's with an eight-under 62.

Playing in the final group with Tony Finau and Justin Thomas, the 33-year-old finished on 19-under for the tournament in front of a packed gallery and secured his 21st PGA Tour win, moving him ahead of Norman's 20.

Though evidently happy he secured the win heading into the U.S. Open, as one of the more vocal critics of LIV Golf, the world number eight made sure everyone knew he was aware he had overtaken Norman.

"Twenty-first PGA Tour win. One more than someone else," he told CBS. "That gave me a little bit of extra incentive today. Happy to get it done.

"It's incredible. Playing with Tony [Finau] and JT [Thomas], two of the top players in the world, and all of us playing the way we did, the worst score in the group was six-under par.

"This is a day I'll remember for a long, long time. I've sort of rededicated myself to the game a little bit, sort of realised what made me happy and this makes me happy."

McIlroy led the entire way on Sunday, starting the final round in a share of the lead with Finau.

He started fast, too, making five birdies on the front nine before commencing the back nine with another three on the bounce.

Bogeys on the 13th and 16th holes opened the door for Thomas and Finau but it was promptly shut, with the Northern Irishman closing out the round with another pair of birdies.

Finau and Thomas finished outright second and third on 17- and 15-under respectively, while Justin Rose tied Sam Burns on 14-under after bogeying the 18th to just miss out on a spectacular sub-60 score.