Tiger Woods made a steady start to the second round of the U.S. Open on Friday after defending champion Rory McIlroy tumbled out of contention on another brutal day for low scoring at the Olympic Club.

One of five players tied for second place at one-under par overnight, Woods safely parred his opening hole to move within two shots of surprise first round leader Michael Thompson, who bogeyed his third hole.

Only two other players in the 156-man field were under par midway through the second round as the notoriously difficult course, with its narrow fairways and deep rough, left most of the world's best golfers just battling for survival.

David Toms, who won the PGA Championship in 2001, was tied with Woods at one under but had yet to start his second round.

They were joined by Jim Furyk, the 2003 U.S. Open champion, who grabbed the early clubhouse lead at one under when he shot a 69, the best score of the day.

"I'm obviously happy, I feel great about the 69," Furyk said. "You have to realize at the U.S. Open par is a really good score and you're going to make some bogeys."

Needing to shoot a low score to make the cut after opening the tournament with a 77, McIlroy fell further behind after carding a 73 to finish at 10 over.

The Northern Irishman had a birdie putt on the last hole to get to eight over but three-putted for a bogey, leaving him in real danger of missing the cut, likely to be around eight over.

World number one Luke Donald, playing in the same group as McIlroy, was also facing an early exit after finishing at 11 over. The Englishman shot a respectable 72 but blew his chances on the first day when he signed for a 79.

"It was a little better today, but little consolation, obviously. It's not going to be good enough to play the weekend," he said.

Graeme McDowell, the 2010 U.S. Open champion, put himself in contention for a second major in northern California with a round of 72 to reach the halfway stage at one over.

The Northern Irishman was alone in second place at two under for most of his round before a late stumble with three bogeys over his last four holes saw him slip back as the wind started to pick up.

"That's what this golf course can do to you in a heart beat," said McDowell.

"To be honest with you, if you had offered me one-over par starting on the first tee yesterday, having seen what I saw yesterday morning, I would have probably snapped your arm off for it."

(Editing by Frank Pingue)