Lee Porter, Jim Gallagher, Jr., Chad Campbell and Robert Gamez share third place at 5-under. Loren Roberts, Rocco Mediate, Phil Tataurangi, Paul Goydos, Bo Van Pelt and Carl Paulson are tied for seventh at minus-4.
Calcavecchia used a birdie tear on the back side at Forest Oaks Country Club to move to the top of the leaderboard. He birdied 13, 14 and 15 before making it five in a row with a pair of seven-footers at 16 and 17.
'I felt great getting to the 12th tee, so I was hoping to really shoot 3- or 4-under and get a little run. To make five in a row was nice,' said Calcavecchia, whose last win came at the 2001 Phoenix Open, where he posted the PGA Tour's all-time record 72-hole total of 256. 'That's the way I play sometimes. I never know when five in a row are coming. It doesn't happen very often, but it's fun when it does.'
The birdie run was spectacular but it might have been Calcavecchia's scrambling around the turn that kept him at the top of the leaderboard.
Calcavecchia snap-hooked his drive at the par-5 ninth and landed under a rock. After taking a penalty drop, he hooked his third shot out of the trees and down the fairway. Calcavecchia played his fourth shot to three feet to save a miraculous par when double-bogey looked like a possibility.
The 41-year-old missed the fairway at 10, then landed in a greenside bunker. Calcavecchia blasted out to eight feet, then made that to once again save an improbable par.
At 11, Calcavecchia found the trees once again and played another hook shot out of trouble. The ball landed in the back bunker and Calcavecchia played a clutch shot out of the sand that stopped a foot from the hole.
'I made seven birdies and no bogeys, and I really honestly think the key to my whole round was nine, 10 and 11,' said Calcavecchia, a member of the 2001 U.S. Ryder Cup team. 'I could have made a couple of doubles and a bogey in those holes and I made three pars. It was three really unbelievable pars and then I hit a good shot on 12 and settled back down and got going after that.'
Stankowski's round included 10 birdies, four bogeys and four pars.
Check out Stankowski's roller-coaster round
'I was all over the map, some good, some bad, some ugly, but it worked out all right,' said Stankowski, a two-time winner on the PGA Tour. 'All in all, if you shoot 6-under-par it's hard to complain too much. I hit the ball good at times and really badly at times, but the bad shots were still OK and I got some good breaks.'
Bubba Dickerson, the reigning U.S. Amateur champion, made his professional debut Thursday and posted a 1-over-par 73.
'I hit it pretty good,' Dickerson said. 'I just couldn't make a putt all day.'
Last year's champion, Scott Hoch, was forced to withdraw from the tournament Thursday morning because of an eye problem. He underwent surgery in January of 2001 but has had complications since and has experienced depth perception problems since a third laser eye procedure on Monday.
Full-field scores from the Greater Greensboro Chrysler Classic