PGA Tour rookie Brent Delahoussaye enjoys a sizzling opening round on Thursday. PGA Tour rookie Brent Delahoussaye enjoys a sizzling opening round on Thursday. (Dave Donnelly/CBC Sports)

Brent Delahoussaye has put his name in the record books at the RBC Canadian Open.

The unheralded American tied a tournament record with an 8-under 62 at St. George's Golf and Country Club in Toronto, taking a two-shot lead after the first round on Thursday.

Four other players have shot 62 at the Canadian Open, with the last being Hunter Mahan in 2007.

It was also the lowest round shot in competition at St. George's — beating George Knudson's 64 in the third round of the 1968 Canadian Open, the last time the championship was held on the course.

"I am shocked," Delahoussaye said. "I knew I was playing well, but I didn't really know how many under I was at one point. I just kind of kept going, kept trying to make birdies."

Delahoussaye is a PGA Tour rookie whose only professional victory came at the 2006 Hooters Tour Classic. His round included seven birdies and an eagle against one bogey.

He's made just three cuts and less than $30,000 US in 2010.

"I haven't played well this year," he said. "It's my first year out and I've been trying too hard like everyone says not to do. It just hasn't clicked. I've been getting in my own way."

Delahoussaye is two shots up on Vance Veazey and Brock Mackenzie and three ahead of a large group that includes Mahan.

Calgary's Stephen Ames and Jon Mills of Oshawa, Ont., both shot 67 to register the best scores among the 18 Canadians in the field.

Ames, who hasn't played competitively since missing the cut at the U.S. Open in June, said the break paid some early dividends.

"I'm happy with the way things have started," said Ames, who fired a bogey-free round.

"I wasn't comfortable with certain things. I think that was my goal … to try and get as comfortable as I could over the golf ball before I actually pulled the trigger, and I think I accomplished my goal."

Mike Weir of Bright's Grove, Ont., struggled to a 2-over 72.

Weir, who pulled out of Wednesday's pro-am with tendinitis in his right arm, refused to blame his play on the injury.

"I don't want to use an excuse like that. Just didn't play well," said Weir. "[It's a] tough golf course. If you hit it in the rough, it's tough around the greens. Rough around the greens [and] very unpredictable.

"But if you drive it well and get it in the fairway you can score, but if you don't, it's a tough golf course."

After a 42-year hiatus at St. George's, players were talking earlier in the week about a single-digit score over four days being enough to win. That appears to be a long shot now.

"I was surprised with how many good scores there are," Ames said. "The greens are very receptive, they're soft. But as the week goes on I think they're going to get a little firmer."

Mills, who has made two cuts in his seven previous Canadian Opens, said playing at home definitely has a different feel.

"You have to not get overwhelmed with everything and just try to stick to your own game and not focus on the people and just stay within yourself. And it can be tough to do with this many people," he said.

Other low Canadians were Adam Hadwin (68) of Abbotsford, B.C., Matt Hill (69) of Bright's Grove, Ont., and Graham DeLaet (70) of Weyburn, Sask.

DeLaet, who started on the back nine, began with three birdies before making bogey on No. 14 and following it with a double bogey on the 15th hole.

"I hit the ball well enough to score but unfortunately the putter wasn't rolling," said DeLaet. "I had trouble finding the speed and I was either leaving them short or running them past the hole on a couple three-putts.

"But I'm happy with the way I'm hitting it so if I can keeping doing that for the next few days I should be in good shape."

Canadian amateurs Eugene Wong of North Vancouver, B.C., Cam Burke of New Hamburg, Ont., Nick Taylor of Abbotsford, B.C., and Dave Bunker of Woodbridge, Ont., all shot 71, as did Calgary's Ted Brown. Joining Weir at 2 over were David Hearn of Brantford, Ont., Chris Ross of Dundas, Ont., and Edmonton's Barrett Jarosch.

Other Canadians in the field were Jeff Puska (73) of Ladysmith, B.C., Ben Boudreau (74) of Longueuil, Que., Victoria's Jim Rutledge (76) and Montreal amateur Beon Yeong Lee (78).

A Canadian hasn't won the event since Pat Fletcher in 1954.