Play was delayed twice throughout the afternoon due to inclement weather. The first round resumes at 8:15 AM ET Friday morning.
Stiles had a birdie putt waiting for him at the 18th when play resumed after the first weather delay that would have given him the outright lead. Upon returning to the course, Stiles' 12-foot try horse-shoed out of the cup.
'It was a lot easier having just to hit the putt than if I had to go hit the shot still,' said Stiles. 'I never really thought about it the whole time during the delay.'
Stiles got things started with a birdie at the first and sank a six-foot putt for a birdie at the third. At the par-5 fifth, Stiles sent his second shot 15 feet from the cup and drained the putt for an eagle.
He added a birdie at the eighth and collected two additional birdies on the inward half for a 64.
'Really, I did everything pretty well today,' said Stiles. 'I drove the ball really good, hit some great iron shots pretty much all day and then made the putts.'
Stiles' co-leader Haas stumbled out of the gate with a bogey at the opening hole but began a remarkable run moments later. Haas two-putted for birdie at the third, added another birdie at the fourth and ran home an 18-foot birdie putt at the fifth to make it three in a row.
At the sixth, Haas knocked a pitching-wedge to 12 feet for a birdie and converted a putt from the same distance for a birdie at the seventh.
The 49-year-old then hit a 9-iron within 12 feet for his seventh consecutive birdie, one shy of matching the all-time record.
'Well, I had never made seven birdies in a row before. Six was my best prior to today,' said Haas. 'I just can't afford to give too many away here, and then it turned around most quickly and I started hitting a lot of good shots and making every putt I looked at.'
Haas found trouble with a bogey at the 12th but recovered with back-to-back birdies starting at the 16th to secure a share of the early lead.
'Golf-wise, for the last year and a half, two years I've really putted well, putted very consistently,' said Haas. 'I've told many people that I still have a passion for the game. That kind of comes and goes, but right now I feel very fortunate to do what I'm doing and be a professional golfer. I've made a living at it for this long.'
Robert Damron shot a 6-under 65 to finish one shot off the lead. David Peoples was also at 6-under par through 16.
David Gossett, Stan Utley and Dennis Paulson finished at 5-under-par 66. Defending champion Len Mattiace was at 5-under through 17 holes when play was called for the day.
'I love coming back here,' said Gossett. 'I feel very comfortable playing here on my home golf course, and I'm working on a lot. It's not like I'm breezing through here. I've got a lot of areas to improve on. It's nice to get off to a good start.'
Kirk Triplett, Bob Estes, John Huston, Paul Azinger, Brenden Pappas, Aaron Baddeley and Jim Gallagher, Jr. were one shot further back at 4-under-par 67.
David Toms was one of several players at 4-under par through 16 holes.