Trevor Immelman emerged as the halfway leader at the Masters on Friday as Tiger Woods used an incredible finish to keep alive his bid for a fifth Augusta crown.
Immelman, who has had an arduous recovery from surgery to remove a benign tumor from his diaphragm, birdied 17 and 18 en route to his second straight 68 and an eight-under total of 136.
Woods, who arrived at Augusta supremely confident after winning seven of his last nine tournaments, blamed blustery winds as he failed to generate any real momentum for the second straight day.
Starting four adrift on even par, the world No.1 opened with a birdie, but gave the shot back at the second and didn't get back in red numbers until a birdie at 17.
He took a big gamble at the last after his tee shot found the trees on the right of the fairway. He punched out away from the hole onto the neighboring 10th fairway.
Woods then muscled a shot straight toward the 18th flag. It came to a premature halt on the green when it hit the ball of playing partner Stuart Appleby.
Woods allowed himself a rare smile when he got the green, then made his par putt to complete a 71 for a one-under total of 143.
"Oh man, it was the only shot I had. Either that or pitch out backwards and leave myself over 200 yards," Woods said. "Great four."
Woods, who couldn't make much out of a good ball-striking round on Thursday, said the swirling winds were the biggest problem on Friday.
"It was quite a fight to try and figure out what was going on," he said. "It was swirling all over the place.
"We were backing off shot after shot," Woods added. "It certainly was not a fast front nine. We played right around three hours. Day of patience for sure."
Woods said the seven shots separating him from Immelman was far from insurmountable.
"Seven back on this golf course, in these conditions, you can make that up," he said.
The biggest 36 hole deficit overcome by a Masters champion was eight strokes, by Jack Burke in 1956. Woods himself rallied from a six-stroke halfway deficit en route to his playoff victory in 2005.
But if Woods's previous form holds true, he'll need to gain ground on Saturday, since all of his 13 major titles have come when he held at least a share of the lead after the third round.
Immelman, who went out early before the winds kicked up, said he owed his lead to solid putting on the treacherous Augusta greens. He sank putts of 15 and 10 feet at 17 and 18.
"I really did hole some unbelievable putts out there," said Immelman, who made 10-footers for birdies at the par-four fifth and the par-four seventh and a five-foot birdie at the par-four 11th.
American Brandt Snedeker, playing his first Masters as a professional after appearing as an amateur in 2004, was in second place after a 68 for seven-under 137.
Snedeker rebounded from a bogey at 16 to finish with two birdies. At 17 he sunk a 40-foot downhill putt that he said he was just intending to get close.
At 18 he fired an eight-iron from 170 yards to 15 feet to set up his closing birdie.
World No.2 Phil Mickelson, tipped as the man most likely to deny Woods a Green Jacket and a chance at a sweep of this year's major championships, posted a bogey-free 68 for a share of third place on five-under 139.
He was joined by fellow American Steve Flesch, who carded a five-under 67 and by England's Ian Poulter, who came in with a 69.
Mickelson said he liked his position heading into the weekend.
"I would love to be in the lead, you always like having shots in hand. But I would have had to press the issue in spots, and I didn't want to do that yet," he said.
Mickelson made birdies from three feet at both the second and third, and picked up a stroke with a 10-footer at the eighth. He was especially pleased with his 30-foot birdie putt at 17, which followed eight straight pars.
Mickelson was also buoyed by his good fortune on 13, where for the second time in two days a shot that appeared headed for the creek stayed dry.
"I'm kind of using that as an omen as well," Mickelson said.
One of Poulter's four birdies came at the par-three 16th, scene of his hole-in-one the day before.
Canadian Stephen Ames posted his second straight 70 for a four-under total of 140, where he was joined by England's Paul Casey, who shot a 69.
Americans Stewart Cink (69) and Arron Oberholser (70), and former Masters champion Mike Weir of Canada (68), shared eighth place on three-under 141, while South African Retief Goosen notched his second straight 71 to head a group on 142.
The halfway cut came at three-over 147.
Overnight co-leader Rose also made it with a stroke to spare, despite a spectacular collapse to a six-over 78 that included a triple-bogey eight at the par-five 15th.
Defending champion Zach Johnson ballooned to a 76 but also got through on 146, while such notable names as Ernie Els, Sergio Garcia and Luke Donald failed to make it.