|Canadian Open first-round leaderboard|
|-7: K Bradley (US); -6: S Lowry (Ire) S Im (Kor), N Taylor (Can), E Van Rooyen (SA);|
|Selected others: -5: G McDowell (NI); -4: D Willett (Eng); -3: R McIlroy (NI); -1: L Donald (Eng), M Laird (Sco); +1: D Johnson (US)|
Northern Ireland’s Rory McIlroy shot a three-under-par 67 in his Canadian Open debut to trail leader Keegan Bradley by four shots after round one.
In the final event before next week’s US Open, McIlroy, 30, dropped two shots but found five birdies in his round.
Ireland’s Shane Lowry fired seven birdies to sit tied for second on six under, one behind American Bradley.
Northern Ireland’s Graeme McDowell is five under, while England’s Danny Willett is four under.
A strong showing could see McDowell secure qualification for the Open, which is being held in his home town at Royal Portrush in July.
The 39-year-old has yet to secure a spot for the tournament, but there are three places available via the Canadian Open for players who have yet to qualify but finish in the top 10.
World number two Dustin Johnson – who will be among the favourites for next week’s third major championship of the season at Pebble Beach – is one over par after struggling early on with five bogeys in his opening nine holes.
Bradley, the 2011 US PGA Championship winner, only added the event to his schedule at the last minute and said he produced one of his best displays of ball striking this year.
“I’m thankful that I did, but I want to keep going,” the 32-year-old said. “It hasn’t been quite the year I wanted, but that can change real quick.
“I knew if I could just put myself in the fairway, which I did today, I was having short irons in, and I’m pretty dialled in right now. I was able to really get that close and then hole those putts.”