MARANA, Ariz. — Tiger Woods led a trio of Americans into the semifinals of the Accenture Match Play Championship today, finally getting on track with a chip-in eagle and easing past K.J. Choi, 3 and 2.

Woods had time for lunch and a quick session on the practice range before playing defending champion Henrik Stenson, who won his 10th consecutive match when Woody Austin gave away consecutive holes to lose momentum and eventually the match on the 18th hole.

Stewart Cink took out U.S. Open champion Angel Cabrera, 3 and 2, to reach the semifinals for the first time, where he will play Justin Leonard, at No. 50 the lowest seeds still around at Dove Mountain.

"Bracket buster," Leonard said as he walked off the 18th green after beating Vijay Singh, who narrowly pulled off another escape.

Woods made 12 birdies in 20 holes and needed them all to beat Aaron Baddeley in the third round, a match of the highest caliber. Choi, meanwhile, had advanced over Paul Casey despite making nothing better than par over the final 11 holes.

Their quarterfinal match was of the par variety.

Woods again hit an opening tee shot into the desert and gave away the opening hole, only to square the match with a 15-foot birdie. They halved the next seven holes, although this is where Choi essentially lost his chance to beat the world's No. 1 player.

He had a putt to win the hole six straight times and missed them all, three of those putts from inside 12 feet. Woods was scrapping along with pars, throwing his club at the bag on a few occasions.

But it all changed at the turn.

Woods came up just short of the par-5 10th green, but chipped in for birdie and lightly pumped his fist. Choi was still 15 feet away for par on the 12th when Woods dropped a 30-foot birdie to go 2-up, and he had control the rest of the way.

"K.J. put a lot of pressure on me with his ball-striking," Woods said. "I just had to hang in there."

So did Leonard in the most fascinating match of the quarterfinals.

For much of the back nine, Leonard had a 1-up lead, Singh failed to hit a single shot that put pressure on Leonard, yet the Texan appeared to be under enormous pressure.

"It wasn't a clean match," Leonard said.

But when he holed an 8-foot birdie putt on the 11th to win his second consecutive hole, Leonard went to 3 up and looked strong. Even after Singh drove onto the par-4 12th green, Leonard was determined to beat him with his wedge, and hit a beautiful pitch to 4 feet.

But his birdie putt lipped out, and that one short miss went a long way in affecting the mood of the match.

With Singh in the bunker on the 13th, Leonard misjudged the wind, came out of his shot and had 80 feet for birdie. He three-putted for bogey to lose another hole.

Singh looked like Houdini for the second straight match. He was 2 down with two holes to play against Pampling in the third round, won the last two holes, then in 25 holes. This was headed in the same direction.

Singh's approach on the 15th bounced hard off the left side of the green and appeared headed into the desert when it hung up in the lush green grass with only a foot to spare. Singh hit a poor chip and was lucky to stay on the green, then holed a 12-foot par putt to halve the hole. On the par-3 16th, Singh went after a sucker pin and landed in the right rough, the toughest spot from which to save par.

But that's what he did, chipping 6 feet by and making it.

Singh finally squared the match with his power advantage, hitting 7-wood to 20 feet for a two-putt birdie.

Leonard played the 18th hole for the first time all week, and he played it to near perfection. Leonard hit his approach to 10 feet, and Singh hit his a foot outside him.

Singh missed — he didn't have a single one-putt birdie all round — and Leonard's winning up curled in the right side.

"I deserved that one," he said.

Cabrera made it through the week as the only player not to reach the 18th green, which was bad news this morning for the Argentine. He couldn't keep up with Cink's birdies, and Cink closed him out with a birdie on the 16th.

Stenson, meanwhile, is the marathon man of Dove Mountain. All four of his matches have gone the distance, and he played 25 holes Thursday to beat Trevor Immelman. He made sure his match against Austin didn't get past the 18th hole, hitting an approach to 2 feet for his 2-up victory.