Marc Leishman takes a selfie with the winner’s trophy after winning the Farmer’s Insurance Open at Torrey Pines Golf Course on Sunday in San Diego. (AP photo)

SAN DIEGO — Marc Leishman realized he had at two-shot lead as he stood over a 6-foot birdie putt on the final hole at Torrey Pines. He also knew Jon Rahm was the only one who could catch him.

That made his final birdie all the more important.

It turned out to be the winner Sunday in the Farmers Insurance Open, much to Rahm’s surprise.

Leishman shot 31 on the front nine to seize control, came up with three big par saves on the back nine and closed with a birdie for a 7-under 65 and a one-shot victory.

“If I wasn’t to win, I didn’t want it to be because of me,” Leishman said. “I wanted it to be because someone made a run, which Jon did. I’m just lucky that he didn’t do it a hole earlier.”

Rahm played so badly at the start — two bogeys and a double bogey through five holes — that he started firing away, and few players are more dangerous. He made an eagle and three birdies over a five-hole stretch to at least have a chance.

His mistake, aside from a bogey on the 15th, was not knowing the score.

He stuffed his tee shot on the 16th to 8 feet, and he went after the pin on the 17th to 5 feet for birdie. Leishman had finished by then at 15-under 273.