Mark Calcavecchia, who also shot 68, played a practice round Tuesday and immediately sent a text message to Woods, who was practicing that day at Southern Hills. He told him the greens were as fast as Augusta National.
"I've never seen them this fast," Calcavecchia said.
Mahan had no trouble with them, if only because he didn't have much space between his ball and the cup. He hit 5-wood into 20 feet for a two-putt birdie on the par-5 second, hit a sand wedge to 2 feet on the third, a 7-iron to 12 feet on the fifth and closed out his birdie run with a 7-iron to 10 feet on No. 7 and a wedge to 4 feet on the eighth.
Casey also got up to speed not with his putting, but his energy level.
After a grueling week at Carnoustie, he played last week in Germany and felt drained. He was still dragging his feet when he arrived in America, which swing coach and CBS Sports analyst Peter Kostis quickly noticed. Kostis figured a simple challenge might help, so he offered to buy Casey dinner if he broke par.
"The opposite to winning dinner was buying dinner," Casey said. "And it worked. It got me going."
One of his birdies came on the 16th, a 656-yard hole that is tough to reach in two and equally difficult when playing the third shot with a wedge over the pond to a shallow portion of the green. Casey was alert enough to realize that Kostis works in the 16th tower, and he stuffed his wedge into 4 feet.
"I was aiming 15 feet left of the flag to the center of the green and I didn't hit the shot I wanted to," Casey said. "I kind of came out of it slightly and pushed it out to the right, and it finished about 4 feet away. I won't tell him that."
Casey played in the final group last year with Woods and Stewart Cink and tumbled out of contention. He hopes for another chance this week, especially with the PGA Championship waiting and Firestone proving to be an ideal place to test one's game.
Joining the leaders was Sabbatini, who hasn't been heard from on the golf course, anyway since winning Colonial. Sabbatini went six holes without making a par, a streak that included three straight birdies. The longest of those putts was 3 feet, and his final two birdies were inside 5 feet.
"The rough is insane out there," Sabbatini said. "By Sunday if we don't get any rain, I don't see that anybody is going to be able to really get the ball close to any holes unless they're chipping."
Anyone not on his game paid for it.
Cink, a winner in 2004 and a playoff loser to Woods last year, failed to make a birdie on his way to a 79. Mike Weir's progress slowed dramatically when he opened with a 77, while Vijay Singh chopped through the rough on his way to a 74.
Phil Mickelson, who has missed the cut in his last two majors, also shot 74.
"It's certainly playing different than most years," Woods said. "Most years, it's raining here, ball is plugging, you've got some low scores. Not this year. Right now, 3 under is leading. And that's a heck of a round here."