Rory McIlroy beat his Ryder Cup team-mate Lee Westwood to reach the final of the WGC Match Play in Arizona.
The US Open winner from Northern Ireland won 3&1 against Westwood and now faces Hunter Mahan, a 2&1 winner over Mark Wilson, in the final.
Victory in Sunday's final would move McIlroy, 22, up to world number one, replacing Englishman Luke Donald.
McIlroy was three down after four holes but staged a brilliant fightback to beat England's world number three.
Westwood went in front on the par-five second, pitching on to five feet for a birdie while McIlroy missed from 22 feet.
McIlroy found a greenside bunker on the third and then the greenside rough on the driveable fourth and Westwood was three up after four holes.
But Westwood missed a putt from 10 feet to save par on the fifth and McIlroy birdied the sixth to bring the deficit down to one.
The Northern Irishman, who would be the youngest winner of the championship should he prevail, drew level at the par-five eighth with a birdie putt from 14 feet.
Then he birdied the ninth, 12th and 13th and, amazingly, after being three down through four holes, was three up after 13.
But Westwood hit back with an eagle on the par-five 15th but McIlroy wrapped it up on the 17th.
Semi-final results (US unless stated, UK and Northern Ireland players in bold):
Hunter Mahan beat Mark Wilson 2&1
Rory McIlroy beat Lee Westwood 3&1
