Chad Campbell surged into the lead at Augusta National with a 5-under 67, while Woods was struggling to keep up in his bid to win a fifth green jacket as the tournament neared its midway point Friday.
"It's special to be leading after two rounds," Campbell said. "Obviously, my goal is to be leading after four rounds. I'm off to a good start, and hopefully I will have a good weekend. This is a special place, a special tournament. I'm glad to be playing well."
Woods normally makes his run here in the second round, but he was still trying to master the bulked-up course — at 7,445 yards, the second-longest in major championship history.
Woods was 1 under for the day and the tournament through 15 holes. He needed to make up five strokes on Campbell, who had a 6-under 138 total after two rounds.
Then came Mickelson, perennial Masters contender Ernie Els, Darren Clarke, Tim Clark and David Howell — all at 142.
"It could have been good," Mickelson said. "I left some shots out there. But the way I look at it is: I'm in good position heading into the weekend."
Ben Crenshaw, a two-time champion, had another day to remember. He shot 72 and made the Masters cut for the first time since 1997.
"This has always been my favorite place," said Crenshaw, who was at 143 and five strokes behind the leader. "For six or seven years, I didn't play worth a darn."
Regarded as one of the up-and-coming stars on the PGA Tour, Campbell needs a major championship to validate his potential. After missing the cut in his first two Masters, he contended last year with a third-round 67, closed with a 75 and ended up in a tie for 17th. He wants to finish the job this time.
Campbell began a run of three straight birdies in Amen Corner. He made a 20-foot putt on the treacherous 12th — perhaps the most famous par-3 hole in the world. He laid up on the par-5 13th, which paid off when he wedged the ball to 10 feet and made the putt. At 14, he smothered the flag with a 9-iron, rolling in a 6-footer to take his score even lower.
Campbell bounced back from his first bogey at 17 with another birdie — his sixth of the round — to finish things off at 18. He again went with the 9-iron from 145 yards, putting the ball within 15 feet and sinking the putt.
"So much has been made of driving and iron play now, but you've still got to putt," Campbell said. "The biggest part of this course is putting."
There were three major surprises on the first day — Mediate, Crenshaw and Arron Oberholser.
Mediate, who slumped badly the last two years because of back problems, began with a 68 and doggedly held on Friday, managing a 73 that looked pretty good with the wind kicking up and the greens drying out.
"I'm very pleased," he said. "I would have been very happy with a 74, to be honest."
Along with Singh (67) and Mediate, the only other player to break 70 in the first round was Oberholser, a Masters rookie who shot 69. He wasn't going away, either, making an eagle at No. 13 and still just four strokes behind Campbell with two holes to play.
Oberholser found himself tied with Singh, who was 3 over for the day — largely because of back-to-back double bogeys at the fourth and fifth holes, and another double at the 13th.
Crenshaw was — and remains — the tournament's biggest stunner. Coming into this year, he had not broken par at Augusta since a closing 68 at the 1995 Masters clinched his second green jacket. Heck, the 54-year-old Texan hasn't even made the cut in nine years.
That streak is over. Crenshaw shot a 71 on Thursday, and he showed no signs of fading in the second round.
Not bad, considering he was talking retirement at the beginning of the week.
"If the course stays dry, it let's a few more people (in). There's a way to play it," Crenshaw said. "The odds are against someone contending that way. But I've been proud of the way I've played mostly."
So was Charles Coody, who goodbye to the Masters with a respectable round. The 1971 champion decided to make this his final Masters at age 68 — a decision that seemed appropriate when he opened with an ugly 89, the worst score of the first round by five strokes.
But Coody bounced back to shoot a 74 on Friday, rolling in a 15-foot putt to save par at the 18th hole.
"I'd like to be remembered as a nice guy and a fairly decent player," Coody said. "I know I'm not a Hall of Fame golfer. But nice guy and good family man, that would be good enough for me."
Coody was actually 1 under through 15 holes, but a bogey at 16 and double bogey at 17 ruined his improbable bid to go out with a round in the red.
"I have a lot of respect for the tournament," he said. "That's one of the reasons I won't play anymore. I don't want to embarrass the tournament."
David Duval was certainly embarrassed by his first two holes. Coming off a miserable 84 on Thursday, he had double bogey at No. 1, then put up a quintuple-bogey 10 at the next hole after driving into a hazard.
Then, the world's former No. 1 player made a stunning recovery, playing the final 12 holes at 5 under — including a 32 on the back side that gave him a 75. It wasn't nearly enough to make the cut, but maybe gave him hope for the future.
Among the others who appeared to be heading home: Chris DiMarco, who lost to Woods in a Masters playoff one year ago; three-time winner Nick Faldo; two-time winner Bernhard Langer; reigning U.S. Open champion Michael Campbell; Colin Montgomerie; and John Daly.