Marana, AZ (My Sportsbook) - Tiger Woods' first tournament back after knee surgery ended earlier than expected on Thursday when Tim Clark knocked the world's best out in the second round of the WGC-Accenture Match Play Championship.

Woods, a three-time winner and the defending champion, lost 4&2 to Clark at the Ritz-Carlton Golf Club.

"I played really well today, I just didn't make enough birdies," said Woods. "I hit one bad eight-iron and one bad drive in two days. Playing in match- play, you're going to have to make birdies and I didn't do that today."

Woods returned to the PGA Tour after an eight-month absence. He had left knee surgery after his epic win at last year's U.S. Open.

Woods, the No. 1 seed in the Bobby Jones bracket, had a relatively easy time of it on Wednesday in his 3&2 first-round victory over Brendan Jones, but Clark, a former Masters runner-up, was much tougher.

Woods started well with a two-putt birdie for the win at two, but Clark pulled even after an amazing, 65-foot birdie putt at the fifth. Woods caught a horrible lie in the bunker at six and made bogey, falling behind 1-down.

That deficit didn't last long. Woods sank an eight-footer for birdie to win the seventh and get back to all-square. The duo halved the next three holes, then Clark took over.

At the par-five 11th, Woods' third shot came up well short of the putting surface. He could not save par and Clark made a little birdie putt to go 1-up. Clark stiffed his tee ball inside four feet at the par-three 12th and watched Woods come up several yards short of the green with his. Clark won that hole to go 2-up.

Woods missed the green at 13 and hit an awkward chip. Clark two-putted for birdie and Woods missed from seven feet to fall 3-down with five to play.

The best player in the game responded the only way he knew how. Woods found a greenside bunker, but holed the sand shot for a birdie. Clark missed his birdie effort and Woods was 2-down.

With a little momentum, Woods hit a terrible drive out of bounds. Woods didn't know the ball was out, so he had to walk all the way back to the tee to hit his third. Clark drove into a bunker and was in a tough position to make par and Woods did his best to apply pressure. From the tee, Woods hit it to 25 feet, but Clark hit a great approach just past the flag on the fringe.

Woods missed his par putt and Clark lagged his birdie down to concession range. The win put Clark 3-up with three to go and Woods would need something remarkable to advance.

He did not get, but watched Clark hit a pretty remarkable shot. Clark hit a great tee ball to three feet at the par-three 16th. Woods missed the green and probably had to hole out to have any chance.

Woods did not, but came close. When the ball stayed up, Woods walked over and conceded the win to Clark.

"Tim is a wonderful player," said Woods. "You know he's going to be consistent. You know he's going to grind it out. He made a bunch of birdies today and I didn't answer him."

The tournament still has some star power left even after Woods' early exit.

Phil Mickelson is the highest-rated player left in the Ben Hogan bracket, although it wasn't easy. Mickelson knocked off fellow Masters winner Zach Johnson, 1-up, on Thursday.

For the second time in as many days, Mickelson established a 4-up lead on his opponent, only to see it evaporate late. Mickelson missed short putts to lose 14 and 15, then Johnson birdied 17 to head to the 18th, 1-down.

Mickelson was able to hold on with a par at the last to match Johnson. However, this is two straight matches where Mickelson let go of big leads late.

"I had a chance yesterday and today on 14 to go dormie-four if I could have made par, and I three-putted there," said Mickelson. "Conditions were tougher today."

Mickelson will face sixth-seeded Stewart Cink in the third round. Cink outlasted third-ranked Lee Westwood in 23 holes.

Mickelson is the top player left in that bracket after No. 1 Vijay Singh lost.

Singh missed a five-foot par putt on the first extra hole to give Luke Donald, ranked ninth, the 1-up victory. Donald won the last two holes in regulation to set up a match on Thursday with No. 4 Ernie Els, who was a 3&2 winner over Steve Stricker. Els hadn't gotten past the second round since 2001.

The Sam Snead bracket has two recognizable Americans and two unfamiliar foreigners.

Jim Furyk, the fourth-rated player, won 4&2 over Martin Kaymer to set up a third-round duel with ninth-ranked Ross Fisher, a 6&5 winner over Pat Perez on Thursday.

Justin Leonard is the seventh seed in that bracket and won 1-up over good friend Davis Love III. Leonard drew Oliver Wilson in the third round after Wilson, seeded 11th, took out Anthony Kim, 2&1.

Clark will meet 19-year-old Rory McIlroy, the fourth seed, who defeated Hunter Mahan, 1-up in the Jones bracket. The other match in the Jones bracket should be spectacular with second-rated Geoff Ogilvy, a former champion, and No. 3 Camilo Villegas.

Ogilvy won the 19th hole to beat Shingo Katayama, while Villegas blew through his first two matches. He won 7&6 on Wednesday, then toppled Miguel Angel Jimenez, 5&4 on Thursday.

The wildest bracket by far is the Gary Player bracket.

The highest-ranked player is Paul Casey, the sixth seed, who eliminated Mathew Goggin, 6&4, on Thursday. Casey will face 15th-ranked Peter Hanson, who moved on with a 2&1 victory over Stephen Ames.

The other half of the bracket features No. 8 Ian Poulter, a 1-up winner over No. 16 Charl Schwartzel, who eliminated Sergio Garcia on Wednesday. Sean O'Hair is Poulter's opponent on Friday after O'Hair took out Boo Weekley, 2&1.