Mike Weir fired a five-under-par 68 in the third round of the PGA Tour's season-opening Mercedes-Benz championship.

At 13-under 206, the Canadian leads Nick Watney by one shot while Daniel Chopra and Jonathan Byrd are tied for third at 11-under.

Weir played in an all-Canadian pairing with Stephen Ames and found himself tied for the lead with Ames for much of the round.

Weir went back in front when Ames bogeyed the 10th and he added birdies at Nos. 12, 14 and 18 coming in.

Ames was a shot back to start the day and is in fifth at 10-under 209 after signing for a three-under 70.

The winner of the 2003 Masters, Weir entered the round with a one-shot lead and birdied the fifth and ninth.  Ames wasted no time grabbing a share of the lead with a birdie at the first. He matched Weir with birdies at numbers five and nine on the Plantation Course at Kapalua, which is the lone par-73 layout on the PGA Tour.

Weir could have put more distance between himself and the field with makeable birdie putts at 15 and 16 but he grazed the lip on both.  He did close with a birdie at 18 but that just put him right back where he started the day.

After his bogey at 10, Ames was unable to make another birdie until 18 but there were plenty of others ready to step in and put pressure on Weir.

Watney had six birdies in a 67 that included consecutive birdies to close the round.  Chopra also carded a 67 while Jim Furyk, Justin Leonard, Brandt Snedeker and Steve Stricker are all at nine-under 210.

"I played exactly the same way I played the first day, pretty much," Chopra said.  "That was my goal, just eliminate the mistakes that I made over the previous rounds in certain areas, and for the most part I was able to do that.

"Every time I made a mistake this week it felt like it was a stupid mistake, and it was a silly bogey. That was my main goal today, was just to eliminate those."

The winner here in 2001, Furyk carded his first birdie at number five and made the turn at two-under for the round.  He got hot coming in, firing five birdies on the back nine, including a run of three straight starting at number 14 and a birdie at 18 to cap his round.

"I had kind of a slow start. I really struggled with my putter early, believe it or not," Furyk said. "I had a lot of — a ton of opportunities to make birdie on the front nine and I was able to make two putts at five and eight, but I left — I missed a little four-footer at nine and missed a bunch of short ones, some very, very makeable putts.

"I actually did make some good strokes on the back nine and got to see some putts go in and really turned it around. When I started that nine I was pretty far back. And to go out there and shoot 5-under on the back, all of a sudden I'm within one right now and I'll probably be within three or four by the end of the day. So from way back to kind of in the thick of things tomorrow."

Defending champion Vijay Singh shot 67 and is at 8-under 211 along with 2007 US Open champion Angel Cabrera and Chad Campbell.