Scotland's Robert MacIntyre won five shots in the final seconds to take a four-shot lead into the final day of the RBC Canadian Open.
The 27-year-old was in trouble early on, with a bogey on the opening round and another one-over-par round after the turn.
A birdie on the 10th hole got him back to par, but another drop shot on the 13th put his bid for his first PGA Tour title in jeopardy.
However, he recovered brilliantly, making three straight birdies before sinking a 30-foot eagle putt on the par-5 17th to head into the clubhouse at 14 under.
“My mentality was great from the beginning, I had no expectations at the beginning of the week,” McIntyre said.
“Today I just hung in there. I didn’t play too well at the beginning, but I felt like every time I lost a ball I would bounce back and maybe hit two good shots on the green and then I’d get one back.
“It never got out of my hands. A little bit of luck, a little bit of myself being in the moment and staying calm. And it paid off in the end with the putt.”
McIntyre was four shots ahead of a trio of Mackenzie Hughes, Ryan Fox and Ben Griffin.
Britain's Tommy Fleetwood shot a bogey-free 64 on Saturday to surge to the top of the leaderboard but then fell back a shot to 9 under.
Rory McIlroy, meanwhile, got back into contention with a five-under 65.
The Northern Irish player returned to the top 10 at seven under after a strong front nine at Hamilton Golf and Country Club.
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“There were still some low scores. It felt like it could have been better, but I got back into the game and hopefully I can get closer to those guys tomorrow,” he said in his post-match interview.
“I did a quick practice last night and felt like that got me back into shape. I just felt like my swing was a little out of sync, so I just worked on the rhythm and the tempo a little bit.”
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