Rory McIlroy threatened to shoot 59 but fell just short as he made his Canadian Open debut a great one by clinching a seven-stroke victory in Ontario on Sunday and then said it was only mission half-­accomplished.

McIlroy carded a stellar ­nine-under-par 61 in the final round at Hamilton Golf & Country Club, matching his career-best score on the PGA Tour.

The four-time major champion finished at 22-under 258, while Ireland's Shane Lowry (67) and American Webb Simpson (68) tied for second place on 15-under.

McIlroy joined Tommy Armour, Walter Hagen, Arnold Palmer, Lee Trevino and Tiger Woods on an elite list of players to have won a Canadian, British and US Open.

It was a near-perfect confidence-­booster ahead of this week's US Open at Pebble Beach.

"I'll probably enjoy tonight and have a couple of drinks on the plane on the way to Pebble, but once I get up in the morning in California I'm not going to going to think about this week," he said. 

"I'm just going to know my game's in good shape and try to win another major."

Sunday's triumph was McIlroy's 16th on the PGA Tour, and he has now won a national championship in six different countries and regions - ­after previous successes at the US Open, British Open, Irish Open, Australian Open and Hong Kong Open.

McIlroy rated the win his best since the 2015 Wells Fargo Championship at Quail Hollow in North Carolina and noted he had also won the week before the 2014 PGA Championship, his most recent major victory, so hoped to repeat that experience this week.