Rory McIlroy and Lee Westwood, each seeking a title to become World No. 1, advanced to a semi-final showdown at the World Golf Championships Accenture Match Play Championship on Saturday. World No. 2 McIlroy of Northern Ireland defeated South Korea's Bae Sang-Moon 3 and 2 while Englishman Westwood, ranked third, defeated Scotland's Martin Laird 4 and 2 to set up a high-stakes semi-final at the $8.5 million event. "It will be a great match," Westwood said. "I hope we both play well and make lots of birdies." Either Westwood, a former World No. 1, or McIlroy, trying to achieve the mark for the first time, would replace England's Luke Donald as the World No. 1 if he wins Sunday's 18-hole final. But before one of them gets the chance to face either Hunter Mahan or Mark Wilson in Sunday's afternoon final, he must conquer the other in a morning semi-final. "It's the match I wanted and the match everyone else wanted," said McIlroy, who at 22 would become the youngest WGC Match Play champion. Not since 2004 have two of the four top seeds reached the semi-finals of the event and not since Tiger Woods and Davis Love met in 2000 have two top seeds met in a semi-final. Mahan beat US compatriot Matt Kuchar 6 and 5 without losing a hole and Wilson ousted Sweden's Peter Hanson 4 and 3 in other quarter-finals to set up an all-American semi-final and ensure the event's first US finalist since Tiger Woods won in 2008. "Hunter has made a ton of birdies this week," Wilson said. "I've got to focus on hitting the green and making that par. I'm not going to change anything about the way I'm playing."