PEBBLE BEACH, Calif.  — Mike Weir popped the ball out of the tangled rough, then watched it hit the green and fall in the hole for a birdie on No. 16 and sole possession of the U.S. Open lead.

Too bad momentum at Pebble Beach on Thursday morning lasted about as long as the trip to the next tee box.

The 2003 Masters champion followed his great shot with a bogey-bogey finish to wind up at 1-under 70. He was tied for the clubhouse lead with K.J. Choi, Ian Poulter and Rafael Cabrera-Bello after a good opening round that, at times, seemed as if it could have been better.

“You don’t want to finish a round like that. It’s never a good thing,” Weir said. “But it wasn’t because I was looking at the scoreboard and looking at where I am in the tournament. Because it’s Thursday, and I just happened to hit a couple of poor shots.”

He wasn’t alone. The sun was shining and the wind was blowing on one of America’s great courses for the opening round, leading to the specter of a brittle course and dry, unreceptive greens for Tiger Woods, Lee Westwood, Tom Watson and the rest with afternoon tee times.

“There are areas on a few greens which are very soft and there are areas where I couldn’t get a tee peg in to repair a pitch mark,” Poulter said.

Woods, who won by a record 15 strokes at Pebble Beach in 2000, got a nice round of applause on the first tee box, then opened play by nearly running his approach shot on No. 1 into the hole. It slithered 12 feet past, though, and he two-putted for one of three straight pars to open his round.

Phil Mickelson played in the morning and the greens were only part of his troubles. He hit one ball onto the beach on No. 17, another off the rocks and careening into the ocean on 18. He left a ball in a bunker on No. 4 and missed a four-foot birdie putt on No. 6. All part of a frustrating day that left this year’s Masters winner at 4-over 75.

“I don’t believe I should have shot over par,” Mickelson said. “I putted horrific. You’re going to make some bogeys, going to hit a couple of bad shots here and there. But I gave myself plenty of opportunities and just couldn’t get the ball in the hole.”

He probably did not do enough damage to put himself out of the tournament. This, after all, was a day in which getting below par wasn’t impossible, but staying there was more difficult. Paul Casey made two birdies over the first five holes to get to 2 under early in his round. A big group of afternoon players were at 1 under, including Steve Wheatcroft, John Rollins and Dustin Johnson, who has won the past two AT&T National pro-ams played each February at Pebble.

But Pebble Beach in February is much different than Pebble Beach in June.

“This course, it looks like it’s wide-open fairway, but in the teeing ground, in the mindset, you look right, look left, either way is very tough,” Choi said. “And you can’t stop in the bouncing, so you’re very scared on the tee shot.”

Cabrera-Bello is making his debut at the majors. He was the first person to tee off on No. 10. No pressure there, right? The 26-year-old Spaniard opened with a birdie and briefly got to 2 under before finishing at 70.

He was one of many who had brief stints alone at the top of the leaderboard.

Mikko Ilonen birdied his first two holes but then began a freefall that left him at 4-over 75.

Sweden’s Robert Karlsson was briefly at 2 under, but hit a chip up to the eighth green that reached the crest of the hill and rolled back, only a few paces from where he started. He made bogey there, the beginning of another freefall. He shot 75.

Soren Kjeldsen of Denmark spent most of the morning in the lead, making three birdies over the first six holes. But Pebble caught up to him, too. He made four bogeys on the back to finish at 1-over 72.

Earlier in the week, Choi said his goal was to shoot par all four days, and if he did that, he figured he’d be in pretty good shape.

After Day 1, he felt even better about it given the way his tournament started — with a bogey and a double on the first two holes. He made six birdies to more than overcome that.

“Every day,” he said, “even par is a good situation.”