ARDMORE, Pa.

Tiger Woods, who has more PGA Tour victories than any player in history other than Sam Snead, never has won a tournament when he was over par after two rounds.

Not in any of his 14 major victories. Or any of his 78 tour titles.

But that might not matter at Merion Golf Club, where being over par is like being overweight at the fat farm.

Woods is at 3-over 143 after 36 holes of the 113th U.S. Open, just four shots behind the clubhouse lead held by Phil Mickelson and Billy Horschel. But, of the players who completed their second round, he was one of only seven who shot par or better Friday.

And it is not getting any easier at Merion.

The course that some thought would be assaulted with low scores already is nastier than an alley cat. And the greens and fairways haven't even begun to get firm yet.

"It's hard with the wind and pin locations," Woods said. "They're really tough. We knew they were going to be in the areas, but we didn't think they were going to be as severe as they are."

It was a long day for Woods, the world's No. 1 player. He was one of 78 players who had to return in the morning to finish his first round. After making two bogeys and a birdie in his final seven holes, he had less than 90 minutes before starting his second round.

He was able to creep up the leader board with a round of 70 that included three birdies and three bogeys. But, most important, it also included big par saves at four holes -- Nos. 5, 7, 8 and 17.

Woods will take par any time he can get it at Merion. And par will become a precious commodity as the course begins to dry over the weekend.

"I don't know how much this golf course is going to dry out, whether or not we're going to start picking up mud on a couple of the shots," Woods said. "I got a couple there today. If it dries out a bit more ... I don't know if they're going to set up the course as difficult as they have."

Woods said it was a good thing Merion was still playing soft and receptive in the second round.

"It would be hard to keep the balls in some of the fairways, but I don't think they would have made the greens, the pins, as severe out there. I don't think they would have, maybe a step easier than they are now."

Woods wasn't done.

"Am I surprised? Absolutely not. Unless you played practice rounds out here and you've seen the golf course, you don't realize how difficult it is. Because the short holes are short, but if you miss the fairway, you can't get the ball on the green. And the longer holes are brutal.

"And this is probably the stiffest of par 3s that we ever face. And then they've thrown some of the pin locations in that they have, and it's really tough."

So is the rough, which has caused even more problems for Woods.

On his first hole Thursday, Woods appeared to hurt his left wrist hitting his approach from the right rough. He aggravated the wrist several other times during the round when he tried to gouge the ball from the rough.

The same thing happened several times in the second round, with Woods shaking the pain from his wrist and even elbow every time he chopped a shot from the high grass.

"It is what it is," Woods said of the injury, which he said he got last month at The Players championship.

What really pains Woods, though, is his failure to win a major title in five years. He has been stuck on 14 since his most recent one -- his Monday playoff victory against Rocco Mediate at the 2008 U.S. Open -- despite having chances in several majors since then, most notably the Masters.

If he does end his drought, it will be the first time he has won a tournament after being over par after two rounds.

"Just keep grinding," Woods said. "You just don't ever know what the winning score is going to be. You don't know if the guys are going to come back. We have a long way to go, and these conditions aren't going to get any easier."