Luke Donald found out first hand how quickly things can change at Torrey Pines during the second round of the US Open on Friday.
Two under par through 10 holes, the Englishman was one stroke off the lead. A pair of bogeys later and Donald was three back with some work to do.
Donald came up with a pair of birdies on the front nine and started the back nine with a par at the 10th.
But he bogeyed the par-three 11th after missing the green and failing to get up and down.
He then dropped another shot at 12 after his approach found the deep rough to the left of the green. He chipped out to about 15 feet but missed his par putt to drop to even par for the day.
After a pair of pars to start, Donald birdied the third to get into the red numbers and he added his second birdie of the day at the par-four seventh.
Donald started the day three strokes behind Kevin Streelman and Justin Hicks but Hicks, who has an afternoon tee-off, was soon alone in the lead at three under after Streelman made a mess of the par-three third hole.
Streelman ended up with a plugged lie in the greenside bunker after his tee shot came up short. He blasted out but his ball went over the green into the brush and his third rolled off the front of the green to a chipping area, from where he needed three putts to finish the hole with a triple-bogey.
He parred his next two holes but had a double-bogey at the sixth before bouncing back with birdies at seven and nine.
Streelman then bogeyed the 12th but battled back with a birdie at 13 and a long par-saving putt at the next kept him three over with four to play and at even par overall.
After tough opening rounds, Padraig Harrington and Paul Casey took on the battle to make the cut and had some success early on.
Harrington, the reigning Open champion, carded a 78 on Thursday but appeared well on his way to bettering that score after playing his first nine on Friday in two under.
He started his round on the 10th and made his first birdie at the par-five 13th. He added a birdie at the par-five 18th and parred the first to start his inward nine.
Casey was trying to recover from an opening 79 and had four birdies and two bogeys through 12 holes. He birdied the second, fifth and seventh on the front nine with a bogey at the third.
He started the back nine with a birdie at 10 but dropped a shot at 12 to sit six over for the tournament.
The feature group of the first two days – Tiger Woods, Phil Mickelson and Adam Scott – tee off at 9.36pm BST.
Looking for his third US Open title, Woods will try to improve on an opening 72 that included a pair of double-bogeys.
Mickelson, who has four runners-up finishes from 17 US Opens, signed for a 71 yesterday and Scott managed a 73 despite playing with a broken bone in his right hand.
Lee Westwood starts his second round at 9.25pm after one of only 11 under-par rounds on Thursday with a one-under 70.