The powerful American was never really challenged in the final round at Glen Abbey Golf Club in Ontario as he added a Sunday 66 to rounds of 68-66-65 to reach 23-under-par and post a three shot win.
Opening with back to back birdies Johnson quickly broke out of a four-way tie for the lead to start the day and with another five birdies against a lone dropped shot enjoyed a comfortable stroll over the closing holes.
That Johnson’s score was bettered by only three players on the day was testament to the dominant nature of his win.
The 32-year-old is now just one win away from life time Tour membership as he equalled the winning records of the likes of Ernie Els, Ben Crenshaw and Tom Kite.
With three wins already in 2018 Johnson is the undisputed World Number One and will head to the PGA Championship at Bellerive in two weeks’ time as the favourite.
Johnson had twice been runner-up at Glen Abbey and said after the round he was glad to finally get across the line as the tournament is unlikely to be held here again.
“It means a lot,” he said. “It’s the last time that RBC’s going to be here, at Glen Abbey, it’s a golf course that I really like, I play well at it. So it definitely means a lot to win here.”
Engaged to the daughter of one of Canada’s greatest ever hockey players, Wayne Gretzky, Johnson said he always gets great support from the Canadian fans.
“I’ve got a lot of fans out here thanks to Wayne and the family, so I appreciate all the support,” he said.
“It takes a lot of work, and a lot of support. I’ve got a great family, with a lot of support from them and then obviously a great team to help me to get to where I’m at.”
The Korean pair of Whee Kim and Ben An shared runner-up at 20-under with Keegan Bradley, who made five eagles for the week, alone in fourth at 19-under.
Mexico’s Abraham Ancer was fifth outright while New Zealand’s Danny Lee was the best of the Australasian players at T6.
Aaron Baddeley, who was at the same score as Johnson through 36 holes, faded over the weekend with scores of 75-73 to eventually finished T65 with Camron Percy the next best of the Australians at T69.
Rod Pampling was the last of the ‘down under’ players to make the cut and finished second to last at 2-under and 77th.
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