SAN FRANCISCO — Maybe all Michael Thompson needs to do to stay in front at the U.S. Open is stay out of trouble.
Same for Tiger Woods.
The Olympic Club had its way with so many of golf’s best again Friday, keeping most players over par and in the rough. Graeme McDowell was 1 under through 10 holes in his second round to move to 2 under for the tournament. That put him two strokes behind Thompson, but he still had to play the more difficult front stretch.
Thompson had a 4-under 66 in a sensational opening round, leaving him three strokes ahead of Woods and David Toms. All three had afternoon tee times.
Top-ranked Luke Donald and defending champion Rory McIlroy were in danger of missing the cut in what would be a swift and stunning exit.
Donald came to the U.S. Open with six wins in the past 18 months, more than any other player. Last year, the 34-year-old Englishman pulled off an unprecedented feat: topping the money lists on both the PGA and European tours.
Now he might miss the weekend for the third time in nine U.S. Open starts.
Donald followed his birdie-free 79 — which even 14-year-old qualifier Andy Zhang matched — with an erratic start in the second round. He had two birdies and three bogeys through 10 holes to drop to 10 over.
McIlroy’s slide is almost as startling.
He mixed two bogeys with a birdie through 10 to fall to 8 over. The 23-year-old from Northern Ireland shattered U.S. Open records last June at rain-softened Congressional, finishing at 268 to break the 72-hole record by four shots, and his 16-under total was four better than Woods’ mark at Pebble Beach in 2000.
What a pushover that course was.
Olympic Club has restored ‘‘golf’s toughest test’’ and then some. Only four players — Thompson, Woods, Toms and McDowell — were under par when the morning groups made the turn. Seven others in the field of 156 were at par.
The tight, twisting fairways on the unleveled Lake Course had most of the field hacking out of rough and digging into sand for shots. Others searched for balls in the colossal cypress trees or pushed putts all over the rock-hard greens. Phil Mickelson did all three in his first round.
Sergio Garcia, who reached the green in two on the 11th, was so upset when he missed a 5-foot putt to make bogey that he took a half-swing at the ball and yelled a couple cuss words.
The two accomplished left-handers in Woods’ group, Mickelson (76) and reigning Masters champion Bubba Watson (78), also faced the prospect of missing the cut.
At least they still had a round to play.
Calm and cool conditions under a light layer of fog provided a majestic backdrop of San Francisco’s steep hills when the first groups teed off shortly after 7 a.m. Blue skies and warmer — but still crisp — temperatures followed, speeding those already fast and fickle fairways.
It could be the last time most players enjoy the serene setting.
The U.S. Golf Association decided this year to eliminate the 10-shot rule in which players within 10 strokes of the lead make the cut. Starting at this year’s championship, the cut will be the top 60 and ties. A number of top-ranked players might not make it to the weekend.
The cut line started was at 5 over or better when the first morning groups made the turn in the second round. In all likelihood, it will be at least 7 or 8 over.
USGA executive director Mike Davis said this week the idea behind the new rule was to limit the number of golfers making the cut — 108 did so Oakland Hills in 1996 — and prevent slow play that could perhaps force a two-tee start in threesomes.
Not that Woods will need to worry about that.
Woods was in control in the first round, finding fairways, sticking greens and avoiding the thick rough and towering trees that line the course built on the side of a hill that separates the Pacific Ocean from Lake Merced. He birdied back-to-back late in his round, including a 35-foot putt that banged into the back of the cup on No. 5.
Thompson, who is 27 and in his first U.S. Open as a pro, made seven birdies — seven more than Donald. He was runner-up in the 2007 U.S. Amateur, which just so happened to be at Olympic Club.