K.J. Choi, overlooked by Gary Player for a spot on last week's International Presidents Cup team, carded an 8-under-par 64 for second place. D.J. Trahan is alone in third place at minus-7.
Warren began on the back nine Thursday and collected his first birdie with a 12-footer at the 11th. At the par-3 12th, Warren hit a 7-iron to 23 feet to set up back-to-back birdies. He came up short of the green at the par-5 13th, but chipped to 7 feet and cashed in on his third birdie in a row.
Warren parred No. 14, then it was another great run of golf that started with a two-putt birdie at the par-5 15th. He sank a 50-footer for birdie at the 16th and capped another birdie run with a 20-footer at the par-3 17th.
'It was just like, 'whoa, something going on here,'' said Warren after draining the improbable birdie putt at 16. 'I'm thinking, 'I've hit the worst shot I hit all day and still made birdie.''
The 30-year-old parred the two holes around the turn, but was able to knock it on in two at the par-5 second. His ball stopped 12 feet from the hole, but rolled down. Warren pulled his eagle putt 5 feet from the hole, but he converted the birdie try to get to minus-7.
At the par-3 fourth, Warren hit a 6-iron to 30 feet and made another long birdie putt. He got to 9 under par with a 14-footer at the seventh, but needed to birdie out for sole possession of the course record.
Warren did not give himself a good look at birdie at the par-3 eighth, when his tee ball landed 40 feet from the hole. He two-putted for par, but matched the course record at the par-5 ninth when he two-putted.
In the end, Warren equaled the record originally set by Davis Love III in 1992 and later matched by Mark O'Meara in 1996 and Jeff Maggert in 1999. It was the lowest round since Love re-designed the greens almost three years ago.
'That's as close to a perfect round of golf as I've ever played,' admitted Warren. 'I was hitting the ball exactly where I wanted to, the right distance. Every putt I got over, I felt like I was going to make.'
Warren has three top-10s this season, but has struggled lately. He has missed 13 cuts in his last 15 starts, including five in a row heading into this tournament.
'I feel like I'm so close to playing good,' said Warren. 'I've been seeing shots the last month-and-a-half that I didn't see most of the other parts of the summer. Yes, it is out of nowhere, but I've seen progression lately, for sure.'
Choi played the course the traditional way and jumped out of the gate with five straight birdies, all within 8 feet. He bogeyed the sixth hole, but countered with a 12-foot birdie putt at seven and a 22-foot birdie putt at nine.
Choi kicked in a short birdie putt at the par-5 13th and took advantage of the next par-5, the 15th. He ran home a 13-foot birdie putt at the hole to get within two.
'He's more into focusing on his game,' said Choi's interpreter. 'Eight under was good for him. Now what his focus is, keep playing this well and keeping it steady.'
Tim Clark, who was a member of Player's losing International side, posted a 6-under 66 and is tied for fourth place with John Huston, J.J. Henry and Hidemichi Tanaka.
John Rollins, James Driscoll, Matt Gogel, Jonathan Byrd, Daniel Chopra, Joe Durant and Scott Gutschewski are knotted in eighth place at 5-under-par 67.
Defending champion Brent Geiberger is part of a large group tied for 104th at plus-1. Adam Scott, who played for the Internationals and is one of two top-10 ranked players in the field, is also at 73. The other top-10 member, Sergio Garcia, shot 3-under-par 69.