Hunter Mahan defeated fellow American Matt Kuchar 6 and 5 on Saturday to reach the semi-finals of the $8.5 million World Golf Championships Accenture Match Play Championship.
Mahan did not drop a hole in advancing to a Sunday morning match-up against either compatriot Mark Wilson or Sweden's Peter Hanson.
Saturday's other quarter-finals send world number two Rory McIlroy of Northern Ireland against Bae Sang-Moon of South Korea and world number three Lee Westwood of England against Scotland's Martin Laird.
Either Westwood or McIlroy would replace England's Luke Donald as the world number one if they manage to win the title on Sunday. Donald was ousted by Ernie Els in the first round.
Mahan won the par-three third with a par for a one-up edge and went two-up when Kuchar missed a four-footer to halve the fifth.
Kuchar blasted his tee shot at the sixth over the green and Mahan won the hole with another par to go three-up.
"The level of game he has, (I was surprised) he couldn't find the putter," Mahan said. "I made some good putts early and putted well after that. I just have a lot of confidence with (the putter) right now."
Mahan went four-up at the seventh when Kuchar missed a 10-footer for par and sank a 10-foot birdie to halve the eighth to maintain the lead, birdied the ninth to make the turn five-up and went six-up by starting the back nine with a par.
Both birdied the par-five 11th and parred the par-three 12th and Mahan closed out the match with a four-foot putt to equal Kuchar's birdie at the par-five 13th.
"It's tough after a beating like that," Kuchar said. "Golf beats you up a lot. You have got to be able to put these things behind you. I didn't have my best stuff and got beaten badly."