The semi-finals of the WGC Match Play Championship will feature a clash between two stars of the fickle format: defending champion Hunter Mahan and 2010 winner Ian Poulter.
England's Poulter put away Steve Stricker 3 and 2 in the quarter-finals, spoiling his American opponent's 46th birthday.
Mahan, trying to join Tiger Woods as the only players to win back-to-back titles in this event, defeated US Open champion Webb Simpson 1-up.
Sunday morning's other semi-final will pit Australian Jason Day against American Matt Kuchar.
Kuchar defeated compatriot Robert Garrigus 3 and 2 in the quarter-finals and Day downed former US Open winner Graeme McDowell of Northern Ireland 1-up.
Earlier Saturday, Day ousted reigning Masters champion Bubba Watson 4 and 3.
McDowell ended Irishman Shane Lowry's dream run with a 3 and 2 third-round victory.
Lowry had toppled world number one Rory McIlroy in the first round on Thursday en route to becoming the first 64th seed to reach the third round of the event.
McIlroy led a parade of top seeds out of the tournament in the first two rounds.
Three-time champion Woods, the world number two and second seed, also exited in the first round, while the overall third, fourth and fifth seeds -- Luke Donald, Louis Oosthuizen and Justin Rose -- all lost in the second round on Friday.
Those marquee names might be gone, but Poulter boasts impeccable match play credentials. His Ryder Cup singles record is unblemished, and he has won both this title and the World Match Play Championship in Spain in 2011.
"I love match play," said Poulter, who got past South African Tim Clark in the third round to book his clash with Stricker.
Stricker took a quick 1-up lead when Poulter bogeyed the first hole as the American birdied.
But Poulter won the next to even the match, and went 1-up with an improbable win at the third, where he snaked in a 40-footer and Stricker missed from seven feet.
Poulter called it "a typical match play swing ... It looks like Steve is going to be going up right there, and I hole, he misses. And from then on I sort of took over and got myself in front."
Stricker was 3-down by the turn and Poulter remained 3-up with three holes to play.
There was a bit of confusion at what proved to be the final hole, the par-three 16th. Poulter missed the green to the right and Stricker was short and chipped to about three feet.
Before Poulter had chipped, someone in the crowd called "Pick it up," and Stricker picked up his ball for a conceded putt.
"I think it was close enough, anyway, but for a split second, it was a little off-putting," said Poulter, who nevertheless finished off the match anyway by holing his own 10-footer.
Mahan came out on top in a tense duel with Simpson, the first time this week that Mahan was taken all the way to the 18th hole.
Neither player led by more than one hole, with Mahan finally taking the lead for good at the 16th when Simpson's par putt failed to drop and Mahan made his seven-footer.
He was looking forward to taking on Poulter.
"I have so much respect for the guy and how he plays," Mahan said. "To me, his determination and his will is his greatest strength. He's never going to think he's out of a hole."
Saturday's two rounds put the tournament back on schedule after snow stopped first-round play on Wednesday. Sunday morning's semi-finals will be followed by the championship match.