Woods shot 31 on the back nine.
AUGUSTA, Ga. (AP) -- Rory McIlroy and Jason Day made the Masters look like child's play over two days, trading flawless rounds that gave them hope of becoming the youngest player in a green jacket since Tiger Woods.
They still face a long weekend at Augusta National -- and now, a once daunting figure.
Woods came roaring back to life late Friday afternoon with a 31 on the back nine that featured a daring shot off the pine straw and an 8-iron he carved around the trees on the final hole for his ninth birdie of the day, and his best round at the Masters in six years.
McIlroy, the 21-year-old from Northern Ireland with a bounce in his step, made his first bogey of the tournament on the par-3 12th but otherwise was solid as ever for a 3-under 69. That gave him a two-shot lead over Day, the 23-year-old Australian who showed off some of his fearless play with a bogey-free 64.
Even as Woods was starting to make a charge toward his 66 to finish three shots back, McIlroy didn't seem overly concerned.
"If you start thinking about anyone else here, if you let your mind wander at all, it can cost you a couple of shots," McIlroy said. "I'll be focusing on my targets and focusing on where I want my ball to go on the greens, and that's all I can do. I don't really care what anyone else does. I don't need to know.
"It will be great for the tournament if he's up there," he said. "But I'm two shots ahead and I'm in a better position."
Besides, the greater mystery might be Woods.
He has teased before in the 17 months since his last win. Even a year ago at Augusta, he was two shots back going into the weekend and never got any closer. The 14-time major champion has not been able to string together two great rounds since he made his return from a sex scandal last year at the Masters.
"I'm just trying to put myself in the mix come Sunday," Woods said. "It's irrelevant who's there. My whole job is to get myself there with a chance with nine holes to go. That's what we've always done. And I've been successful at it in the past by doing it that way."
If his name on the leaderboard means anything, Saturday might be a time to find out.
And if the next generation of players is serious about becoming a star, the Masters would be a great place to prove it.
"I've played two good rounds to get myself here in this position," said Day, who is making his Masters debut. "Obviously, I'm not going to back down because I've got lack of experience."
McIlroy was at 10-under 134, the lowest 36-hole score at the Masters since 2005. He has tied for third in the last two majors, although this will be his first time in the final group on the weekend at one of golf's biggest event.
It looked as though he might build a big lead going into the weekend until he stalled on the back nine, and now 10 players are within five shots of the lead on an Augusta National course where positions can change quickly.
K.J. Choi three-putted for bogey on the 18th for a 70 and put him tied with Woods at 7-under 137. Another shot back was former U.S. Open champion Geoff Ogilvy, who overcame a four-putt double bogey and a three-putt bogey on par 5s for another 69. He was tied with big-hitting Alvaro Quiros, who had a 73.
Fred Couples, the 51-year-old wonder at Augusta, somehow got into the mix, bad back and all. Couples shot a 68 and was in the group at 139 that included former PGA champion Y.E. Yang (72), 22-year-old Rickie Fowler (69) and Lee Westwood, the runner-up at Augusta last year who got back into the mix with a 67.
Experience never hurts at the Masters.
"I'm playing my 12th one. I don't know how many they are playing, but I don't think it's that many," Westwood said. "I've been in the situation before, probably more recently than anybody around this golf course. I think it's a big advantage."
Then again, Colin Montgomerie said the same thing when he was paired with a 21-year-old Woods in 1997 going into the weekend. Woods blew him away with a 65 and was on his way to a 12-shot victory.
It doesn't figure to be that easy for McIlroy, even as easy as he has made it look over two days.
His swing looked strong as ever when he pounded a driver on the fifth hole, leaving him a wedge that he hit to 6 feet for birdie, and another big tee shot set up a sand wedge to the back pin on No. 9 to 4 feet. He bounced back from his lone bogey with a 6-iron into about 10 feet for eagle on the 13th, though he missed the putt.
McIlroy never put himself under much pressure. He was having so much fun that he wasn't even paying attention to Day, one of his playing partners, who was slashing out of the pine straw and firing at flags, piling up one birdie after another.
"We had a lot of fun out there," McIlroy said. "I didn't even realize Jason was going so good. I saw he was 6 under on the 15th and thought, 'This is going to be a decent round.' We just fed off each other. The crowd got behind us."
McIlroy, Day and Fowler were quite the group -- ages 21, 22 and 23. The more important number was 18 birdies they made. McIlroy's only regret was not making as many putts as he would have liked.
"I can't really complain," he said. "I'm in the lead going into the weekend at the Masters."
He's just not in the clear.
Woods made sure of that with three straight birdies around the turn -- all of them inside 4 feet -- a clutch par save on the 11th and three consecutive birdies starting on the 13th, again all of them from close range.
"I played myself back in the tournament," Woods said. "I'm three back, and we've got a long way to go. It's going to be fun."
Phil Mickelson has far more work to do.
The defending champion played more aggressively, but failed to save par too often when he missed the green. Mickelson also failed to birdie the par 5s on the back nine and had to settle for a 72 that put him eight shots behind.
"There's a lot of golf left in this tournament, and I'm going to be making a run at him and the other guys ahead of me," Mickelson said.
Asked what gives him confidence he can make a move, Mickelson replied, "Three green jackets."
The cut was at 1-over 145, matching the lowest ever at Augusta. Among those going home are the last three major champions -- Martin Kaymer, now in danger of losing his No. 1 ranking; Louis Oosthuizen and Graeme McDowell.
Woods' 66 was his best round at Augusta since he shot 65 in the third round of 2005, which also is the last time he won the Masters. The two players in front of him have only three wins between them, none in a major.
But that's the thing with so many kids. They don't seem to care.
"I'm in the field. I'm in position. I have a chance to win," Fowler said. "I think any place is a good place for a first win, and I would love it to be here."