Carl Pettersson shot a tournament-record 10-under-par 60 to haul himself into contention heading into the final round of the Canadian Open at St George's.
Pettersson's round featured two eagles, seven birdies and a bogey and moved him to 11 under, four strokes behind joint overnight leader Dean Wilson who went round in 65 for the third day in succession to move to 15 under.
Swede Pettersson is joined in a share of second place with Tim Clark, who led alongside Wilson after the second round, and Bob Estes.
Pettersson shot 71 and 68 over the opening two rounds and it was touch and go as to whether he would even make the cut, and he admitted to his delight at the turnaround.
"I thought I was going to miss the cut yesterday," Pettersson said on www.pgatour.com.
"We got finished with the round and it was right on the borderline. Me and Jay Williamson were actually watching the computer to see if we were going to make the cut, and had a few Canadian beers in there."
"That settled me down, I think. Maybe that's what did it."
Pettersson's exploits saw him break the previous Canadian Open record of 62 held jointly by six players, among them Brent Delahoussaye, who achieved the feat on Thursday, and Kevin Sutherland, who posted the total on Friday.
Pettersson only just fell short of a 59 when his 30-foot birdie putt on the 18th narrowly missed the hole.
"Obviously I'm happy with the round, but I would have loved to have seen that putt go in," he added.
Wilson hit seven birdies and two bogeys on his way to another five-under round. His run of three birdies in a row on holes nine, 10 and 11 shaking off the attentions of South African Clark, who had matched him over the first eight holes.
Clark's round failed to spark over the back nine, however, and he ended the day with a 69 - three birdies and two bogeys - to fall off the pace.
Estes went round in 66 to complete the trio on 11 under.
Bryce Molder (63), Sutherland (65), Trevor Immelman (65) and Brock Mackenzie (68) were one shot further back in a share of fifth.