Tiger Woods felt he had cause for optimism after carding a three-under 67 in his final round at the US PGA Championship, although he was a long way short of title contention.

The 15-time major champion was out of the running in San Francisco heading into Sunday's last 18 holes after consecutive 72s left him two over par for the week.

There was improvement from Woods as the tournament came to a close, however, carding three birdies across the first seven holes.

Although a bogey followed at the eighth, the American made two more gains on the back nine before finishing in disappointing fashion with five at the par-four 18th.

Woods' best score of the week meant he was eight shy of Dustin Johnson as the leaders prepared to head out.

"What I got out of this week is that I felt I was competitive," Woods said.

"If I would have made a few more putts on Friday early on, and the same thing with Saturday, I feel like would have been right there with a chance come today.

"It didn't happen, but I fought hard. That's golf. We lose way more tournaments than we win."

Explaining his fourth-round performance, he added: "I drove it like I did on Friday, my irons were a little crisper and I hit better putts.

"I wanted an under-par tournament score yesterday and made it happen today."

Indeed, Woods fared better than some of the other big names out on the course early on Sunday.

Rory McIlroy was struggling to improve his even-par overall score in an inconsistent round until following a birdie at the 15th with an eagle at the next, while Phil Mickelson finished with a double-bogey that left him four over for the week.

However, Jordan Spieth belatedly found some form, recovering to the same score as Mickelson with a 67.