Luke Donald avoided making the same mistakes twice to remain well in contention for a first Major title at the US Open Championship at Merion.
Donald held a one shot lead over five-time US Open runner-up Phil Mickelson when play was suspended due to darkness on Thursday evening following two delays for bad weather totalling more than four hours.
Play resumed at 7:13am this morning and Donald parred
the difficult 14th and 15th to remain four under.
But the 35 year old then three-putted the 16th and 18th - he also badly misread a birdie putt on the 17th - to card a two under par 68 and finish one behind Mickelson.
"There was a complete switch in wind and obviously a big drop in temperature (from yesterday)," said Donald, who has never recorded a top-ten finish in the US Open and last led a Major at the 2006 US PGA Championship.
"It meant 14 and 15 are playing long but it sort of made 16 and 18 easier and that's why it's a little disappointing to come off those two holes making bogey, despite hitting the greens."
Around 90 minutes later Donald was back on Merion's East Course to begin his second round and after a par on the 11th, he holed from 20 feet for birdie on the 12th and then landed a delicate chip from over the 13th green for another.
He was unable to save par from a plugged lie in a bunker on the 15th, but this time got through the closing holes with three pars to lie three under alongside Mickelson, who was not due out until 3:41pm local time.
Playing partner Lee Westwood had resumed on one under after a double bogey on the 12th yesterday when his third shot to the par four 12th clattered into one of the wicker baskets used instead of a standard flag and rebounded back off the front of the green.
He bogeyed the 17th on his way to a level par 70 and felt he was still in a good position but quickly found trouble in the second round, carding four bogeys, a double-bogey and two birdies in his first nine holes to drop to four over par.
That was the same score as World Number One Tiger Woods, who had carded an opening 73 and was one over par for eight holes of his second round, while playing partner Rory McIlroy was one under for the same stretch and two over for the tournament.
Woods had winced in apparent pain from his left arm on several shots out of the rough but said: "It is what it is and you move on and I've got to get ready for this next round in a little bit.
"It's one of those golf courses where there's some easy holes and there's some hard holes that follow. You've got to take care of the easy holes and try and get through the hard ones and for some reason I left myself quite a few putts in there where they were easily makeable and I didn't make any."
While par fives on most courses offer the chance for birdies, Merion's measure 556 and 628 yards respectively and Donald made six on both.
He missed a short par putt on the second after going from rough to greenside
bunker and then got up and down from more sand on the fourth just to rescue a bogey.
A birdie in between on the third limited the damage and at two under he was one of only three players in the tournament currently under par, Mickelson and Colsaerts the others and still in the clubhouse.