Jim Furyk followed his historic second round 59 with a two under par 69 to grab the outright lead at the BMW Championship.
The American Ryder Cup star took ten shots more than his incredible Friday performance, which had seen him become only the sixth player to break 60 on the US PGA Tour, but by reaching 13 under for the week he shook off Brandt Snedeker to take a one shot lead.
"The goal was to go out and shoot a good number today, get myself in position to win this golf tournament," Furyk said.
"It could have been better out there. I dropped that shot at 18 - it was probably one of the easier holes of the day. But I've got myself in good position, so rather than harp on the last hole, I'd probably tend to want to think about tomorrow and what I have to do to try to win a golf tournament."
Steve Stricker moved into second place with a seven under par 64, with Snedeker slipping to third with a 71.
South African Charl Schwartzel continues to lead The European Tour Challenge after a 69 took him to eight under and a share of sixth.
Ryder Cup partners Luke Donald and Sergio Garcia improved their chances of qualifying for next week’s Tour Championship with rounds of 67 and 69 respectively which left them in a share of 11th on six under.
FedEx Cup leader Henrik Stenson carded a four under 67 to climb ten places into a share of 18th.