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.

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.

In the semifinal against Jim Furyk, he had to make a 7-foot birdie putt to avoid going 2 down with two to play.