SAN FRANCISCO - Rory McIlroy won a tournament as the No. 1 player in the world.

Only at the Match Play Championship does this pass as newsworthy.

In the 17-year history of golf's most unpredictable tournament, only one other player has gone undefeated over five days as the No. 1 seed. That was Tiger Woods, who did it three times, the last occasion seven years ago in the Arizona desert.

Woods needed as much good fortune as McIlroy, who somehow outlasted seven opponents — including three in one day — to capture his second World Golf Championship title on Sunday at TPC Harding Park.

"Physically, I feel fine," McIlroy said after his 4-and-2 win over Gary Woodland in the championship match. "But mentally, it was a grind."

He played 121 holes in five days, including 35 holes on Sunday after getting six hours of sleep.

Three times, he was trailing in his match when he stood on the 17th tee.

Four times, he watched his opponent stand over a putt that would have knocked him out.

Asked to name his most significant shot of the week — and there were plenty of good ones — McIlroy didn't hesitate. He went straight to the Friday match with Billy Horschel, who was 2 up with two to play. McIlroy faced a 30-foot birdie putt on the 17th hole that simply had to go in.

"Basically, I don't hole that and I'm going home," he said as he signed tournament flags after his win. "I don't even get through to the (final) 16."

This was a week when just about everything went right for McIlroy, except for his plans to watch the Manny Pacquiao-Floyd Mayweather Jr. fight in Las Vegas. He wound up giving his floor seat to a friend who had been in the upper level of the MGM Grand.

McIlroy watched the fight in a corner of the interview room. There was pizza and beer. The next evening, there was a trophy.

He wound up taking Horschel to overtime and beating on the 20th hole. He was on the verge of another loss in the quarterfinals until Paul Casey hit a bad chip and a bad putt to make bogey and later missed an 18-foot birdie putt on the 20th hole. They had to return Sunday morning to finish the match on the par-5 opening hole.

McIlroy had 60 feet from the fringe, mud on his ball. Making it worse, he had not practiced on the putting green, only on the chipping green, which was not the same speed. He managed to lag it with perfect pace, and the two-putt birdie won the match.

"It was down to preparation," McIlroy said with a grin.

In the semifinal against Jim Furyk, he had to make a 7-foot birdie putt to avoid going 2 down with two to play. Then, he hit 7-iron to 4 feet for birdie, and he finished the match with a 45-foot eagle putt across the green.

The last match lacked energy, and except for a brief moment on the back nine, the outcome was inevitable. McIlroy won four straight holes when Woodland lost his way off the tee. Woodland rallied behind a few mistakes by McIlroy, and he had a 4-foot par putt on the 13th hole to get the deficit to 1 down.

He missed, and that was that.

"My putt drops on 13 and it's a different ball game," Woodland said. "But I missed that one. And he was like a shark. Smelled blood, and it was gave over quickly."

Woodland lost the next hole with a bogey, and he conceded the match on the 16th hole.

McIlroy has led seven of the last eight rounds in the majors, winning the British Open and the PGA Championship. He already has won twice this year. There's a reason he is No. 1 in the world. And yet it was the format that required so much luck, and so much timing, as is the case just about every year.

Woods won at Dove Mountain as the No. 1 player in 2008. In the opening round, he was 3 down with five holes to play against J.B. Holmes when he made three birdies and a bending 35-foot eagle to rally. In the third round that year, he could only watch as Aaron Baddeley had a 10-foot putt for the win, and missed.

When he won at La Costa in 2004, Woods again was on the ropes to John Rollins when he won the last two holes for a 1-up victory, helped by Rollins missing the green with a wedge in his hand on the final hole.

It's not easy for any of the 64 players to win this, let alone the best. This was only the sixth time in 17 years that the No. 1 seed even reached the semifinals. Woods lost in the championship match in 2000 at La Costa, and Ernie Els was the No. 1 seed when he lost in the semifinals to Pierre Fulke in Australia a year later.

So as McIlroy headed to Florida to celebrate his 26th birthday, it was hard to measure his form.

He really didn't play much differently than he did at the Masters, when he was fourth without a chance of winning, or at the Arnold Palmer Invitational, where he tied for 11th. Had this been stroke play, there's no telling where he would have finished.

What mattered was winning — his 16th worldwide and 10th on the PGA Tour.

"No matter what format it is," McIlroy said, "it's always nice to get a trophy."