Bubba Watson dropped three shots on the back nine to fall into a three-way tie for the lead after three rounds at the Travelers Championship on Saturday.
The former champion had extended his two-shot overnight lead at TPC River Highlands by picking up three strokes in an outward 32 as he took the tournament by the scruff of the neck.
But the American gave them all back coming home to blow the tournament wide open as he was joined on 10-under-par by compatriot Charley Hoffman and Graham DeLaet of Canada.
"I hit some shots that were really good, some quality shots. I got a couple bad breaks too, but that's golf," Watson said. "I still have a shot on Sunday and that's what we're looking for when we're playing."
DeLaet posted the mark after a run of four birdies from the 10th in a joint round-of-the-day 65 while Hoffman carded a 66 in which he picked up four shots in the first 10 holes.
Chris Stroud and Nick O'Hern of Australia are a shot back while veteran Ken Duke fired a 65 to get within two of the leaders.
Watson's capitulation has also opened the door for those on seven under par, a group of seven players that includes US Open champion Justin Rose and one of his big rivals at Merion last week, Hunter Mahan.
"When I've gotten on a good run of form I have kept it going for two or three weeks. That's the goal now," Rose said. "I've been playing really well this week."
However there was disappointment for Padraig Harrington, who began the day just two behind Watson but could do no better than a 72.
At six-under he is four off the lead with Ian Poulter a further two behind following a round of 67. Lee Westwood just made the cut but had a horrible start to his third round before rectifying matters with an inward 31, returning a 69.