Mahan hit a series of remarkable wedge shots in beating Ian Poulter, four-and-three, in his semi-final. He twice hit difficult chips inside five feet to win holes and then seized control with a chip-in from about 70 feet on the 12th hole to take command.
Day defeated Poulter in the consolation match, one-up.
It was the first all-American final in five years at the Match Play Championship, and Kuchar’s win gave the Americans a clean sweep of the PGA Tour’s West Coast Swing for the second straight year.
He moves to No. 8 in the world and picked up US$1.5 million, earning just over US$3.2 million from his past two wins.
Kuchar and Woods are the only former US Amateur champions to win the Match Play Championship. Kuchar won the Amateur in 1997, the year after Woods turned pro. He recalls being in the semi-finals with three Walker Cup players and feeling out of his league.