Keegan Bradley shot a 7-under-par 63 on Thursday to grab a one-stroke lead after the first round of the RBC Canadian Open in Hamilton, Ontario.

Bradley was even par through six holes at the Hamilton Golf & Country Club before going on a tear that saw him reel off five consecutive birdies and seven birdies overall on his final 12 holes.

“It was solid almost top to bottom,” Bradley told the Golf Channel. “I hit almost every fairway, almost every green, then holed some putts. With me, it’s all about the putter. If that thing gets going, I can do stuff like today.”

Bradley is one shot clear of a group of five players at 6 under that includes Nick Taylor, who is one of 12 players in the field attempting to become the first Canadian to win the country’s national event since Pat Fletcher in 1954.

Also shooting 64s on Thursday were Roberto Castro, Ireland’s Shane Lowry, South Africa’s Erik van Rooyen and PGA Tour rookie Sungjae Im of South Korea.

Adam Hadwin, the most successful Canadian player on Tour over the past several years, is among a group of eight players at 5 under. That pack also includes FedEx Cup leader Matt Kuchar and former U.S. Open champion Graeme McDowell, a Northern Irishman who spent hours on Tuesday trying to locate his clubs from Air Canada.

Top-ranked Brooks Koepka, playing for the first time since winning the PGA Championship last month, is at even par.

So, too, is sixth-ranked Justin Thomas, who added this event last Friday after missing the cut at the Memorial.

Like Koepka, Rory McIlroy is making his debut in the event, using it as a tune-up for next week’s U.S. Open. The fourth-ranked Northern Irishman is four shots off the lead after carding a 3-under 67 on Thursday.

Defending champion Dustin Johnson, ranked No. 2 in the world, is at 1 over, as are Bubba Watson and Spain’s Sergio Garcia.

Bradley will have to keep up his phenomenal all-around play to hold off the deepest field the Canadian Open has seen in recent memory. Bradley entered the week ranked No. 37 in the world after missing the cut in two of his past three events. His most recent victory came at the BMW Championship last September, and Bradley has only two top-20 finishes this year.

He hit 12 of 14 fairways Thursday and all but one green while needing only 29 putts during his bogey-free round.

“Today was one of the best of the year, if not the best,” Bradley said of his ball-striking. “I knew that if I just put myself in the fairway, which I did today ... I was having these short irons in. I’m pretty dialed in right now, so I was able to really get that close, and then hole those putts.

“It’s a lot of fun ... it’s a lot more fun doing that.”

NOTES: Bradley came in fourth place in the Canadian Open last year. ... The event moved from July to June for the first time since 1989. ... Scott Piercy (263 in 2012) holds the tournament scoring record at Hamilton G&CC, which first hosted the event 100 years ago. ... Johnson is seeking to become the seventh player to successfully defend a Canadian Open title.