* Poulter ends Stricker's birthday run
* Mahan edges past Simpson 1up
* Kuchar beats Garrigus 3&2 (Adds quotes, detail)
By Mark Lamport-Stokes
MARANA, Arizona, Feb 23 (Reuters) - Defending champion Hunter Mahan and 2010 winner Ian Poulter set up a mouth-watering showdown in the last four of the WGC-Accenture Match Play Championship by winning their quarter-finals on Saturday.
American Mahan triumphed 1-up after a tight match with U.S. Open winner Webb Simpson while Briton Poulter advanced with a commanding 3&2 victory over American veteran Steve Stricker on a sun-splashed afternoon at Dove Mountain.
Sunday morning's other semi-final will be contested between American Matt Kuchar and Australian Jason Day, at 25 the youngest player left in the draw.
Kuchar became the first player to reach the last four, beating compatriot Robert Garrigus 3&2, before Day battled past Northern Ireland's Graeme McDowell 1-up in a closely contested encounter.
Most eyes, however, will be firmly focused on the battle between Mahan and Poulter who are both bidding to reach the Match Play final for a second time.
Poulter will be a little fresher, having gone 4-up on 2001 Match Play champion Stricker after 12 holes before wrapping up his win by sinking a 10-foot par putt at the short 16th.
The flamboyant Englishman, who is renowned for his matchplay grit and superb putting, went ahead for the first time at the par-three third where he sank a double-breaking 40-footer for birdie while Stricker missed his attempt from seven feet.
"It looks like Steve is going to be going up right there, and I hole, he misses," a smiling Poulter told reporters after recording six birdies and an eagle in 16 holes.
"And from then on I sort of took over and got myself in front. I knew I had to bring my game this afternoon to be able to match up against Steve."
Stricker, who celebrated his 46th birthday on Saturday, had reached the quarter-finals with a sizzling eight-birdie display earlier in the day when he beat fellow American Scott Piercy 1-up.
In the last quarter-final match out, Mahan and Simpson were all square after four holes before Mahan sank an 18-foot birdie putt at the par-four fifth to go 1-up.
Simpson got back to level with a birdie at the eighth, where he struck a wedge to three feet, but Mahan again edged in front when he rolled in a 26-footer to birdie the 10th.
Though Simpson pegged it back by sinking an eight-foot birdie putt at the par-five 13th, the match effectively turned at the short 16th where both players ended up in the left greenside bunker off the tee.
Simpson failed to get up and down, missing a 10-footer for par, while Mahan knocked in a seven-footer to go 1-up, a lead he maintained over the next two holes.
"Difficult match against Webb," said Mahan, who won last year's title with a 2&1 victory over Rory McIlroy in the final. "Great competitor, great player. I knew it was going to be a tough one, and it was.
"It was really a seesaw battle. I don't think either one of us really gained too much momentum, it was so back and forth."
Asked to assess the challenge of facing matchplay specialist Poulter in the last four, Mahan replied: "He has a great short game and he's a great putter.
"But to me his determination and his will is his greatest strength. He's never going to think he's out of a hole.
"The greatest challenge with him is just staying in my own game and just playing, not getting to kind of playing at his speed or anything. I just need to hit quality shots and put pressure on him that way."
Earlier in the day, the third round was played to get the tournament back on track after only three-and-a-half hours of golf was possible on Wednesday because of driving sleet and then snow at Dove Mountain. (Reporting by Mark Lamport-Stokes; Editing by Gene Cherry/Greg Stutchbury)