Mahan had gone 169 holes over 11 matches without trailing in this wild tournament until Kuchar won the fourth hole of their championship match with a par, and Mahan never caught up. Kuchar took advantage of a series of miscues to build a 4-up lead at the turn, and then held off a noble challenge by the defending champion.

There was never a dull moment on the back nine. Only two holes were halved, and those were with birdies.

But for all the great shots, the match ended when Mahan went from a tough lie in the bunker to a bush in the desert, and it took him four shots to reach the 17th green. Kuchar wound up winning, 2 and 1, when Mahan removed the stocking cap he used to fight the cold desert air and conceded Kuchar a short birdie putt.

It was the first World Golf Championship title for Kuchar, and it follows a year in which he won The Players Championship. Kuchar became the second player in the last three years to win the Match Play Championship without ever playing the 18th hole.

“It seems like each hole there’s so much momentum riding and so much pressure on every hole,” Kuchar said. “To come out on top after six matches of playing the top 64 guys in the world, it’s an incredible feeling.”

Mahan was trying to join Tiger Woods as the only back-to-back winners, and he gave it a good shot despite the big deficit halfway through the match.

“Just had a bad stretch against Matt on the front nine there that put me just a little bit too far behind,” Mahan said.

In a strong, cold wind — the wind chill index reached a low of 37 degrees on the final day — Mahan made a long two-putt par to win the 10th, and played a tough chip from the mound of a bunker to about 6 feet for a birdie on the next hole, cutting the lead in half.

Mahan followed with a tee shot into about 10 feet on the par-3 12th, the momentum squarely on his side. Kuchar, however, followed with an 8-iron to just inside 15 feet and made the birdie putt.

“The shot was certainly good, but the putt was really crucial, and when that went in, I felt like I was still in control of the match,” Kuchar said. “Had that putt not gone in, it would have been only a 1-up lead, and I think the match was in anybody’s hands at that point.”

On the par-5 13th, Mahan hit a poor approach from the fairway and Kuchar got up-and-down to restore his lead to 3 up.

Kuchar came up with one more clutch shot. With a 2-up lead on the 304-yard 15th hole, the breeze at his back, Kuchar chipped about 10 feet past the hole with Mahan only 6 feet away for birdie. Kuchar holed the putt and escaped with a halve.

Mahan won the 16th with a two-putt par when Kuchar’s tee shot bounced off the corporate tents behind the green, and it look as though the match would go down the 18th for the first time in nine matches for Kuchar. Both hit into the fairway bunker, but Mahan’s ball was slightly sunk in the sand, and his approach never came close to reaching the green. Instead, rolled through a patch of desert until it lodged in a bush.

Kuchar’s record in this event improved to 15-3, the highest winning percentage of anyone who has played at least 10 matches. He has reached the quarterfinals each of the last three years, and this time went all the way.

He played 96 holes and only trailed after four holes all week.

Kuchar polished off Jason Day of Australia in the semifinals Saturday morning, 4 and 3.

Mahan hit a series of remarkable wedge shots in beating Ian Poulter, 4 and 3, in his semifinal. He twice hit difficult chips inside 5 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, 1 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 $1.5 million, and now has earned just over $3.2 million from his last two wins.

Kuchar and Woods are the only former U.S. 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 semifinals with three Walker Cup players and feeling out of his league.

That wasn’t the case this year, even against Mahan. Collectively, they have a 27-4 record at this event the last three years.

“The difference today I think is just all that experience now,” Kuchar said. “I step up to a first tee and I feel confident and I feel like I belong out here. Back in ’97, I was so new to it, I wasn’t sure I belonged. I loved being out there, but it was … I was way more nervous than I am today. ”