By Larry Fine
ARDMORE, Pennsylvania (Reuters) - Luke Donald, who surged into the U.S. Open lead just as first-round play was suspended on Thursday, slipped out of it after completing the difficult finishing holes at Merion Golf Club on Friday.
Bogeys at the par-four 16th and the par-four last gave the Englishman a round of two-under-par 68, one stroke behind first-round clubhouse leader Phil Mickelson.
World number six Donald, seeking his first major title, leapfrogged Mickelson into the lead when he posted his third straight birdie of the weather-interrupted round on the par-three 13th hole to reach four under par just before play was suspended due to failing light.
Returning for a 7:15 a.m. start, Donald encountered different conditions and more difficult holes on a chilly morning at Merion with intermittent rain.
"A complete switch in wind and obviously a big drop in temperature," the former world number one said. "So those holes are playing long."
Donald, who once had an impressive streak of 449 successive holes in competition without a three-putt, was surprisingly undermined by his putter.
The 35-year-old Briton three-putted the 16th hole and the 18th.
"Misreads," said Donald, a winner of five PGA Tour events and seven titles on the European circuit.
"Certainly those last five holes are very, very tough."
Donald said despite softened conditions following torrential rains in the last week, the relatively short Merion layout remained a stern test.
"I think everyone thought that as soon as the course got wet it was going to play easy," said Donald. "The scores certainly aren't showing that.
"The tough holes are extremely tough. It does give you a little bit of balance with some of those shorter holes, but you really need to play those tough ones well."
Donald only had about 90 minutes to recoup after heading off to begin his second round.
"I got no choice. Grab something quick to eat, hit a few balls and get out there," he said. "I think it's good to have a good turn around, I'll still be warm."
(Reporting by Larry Fine; Editing by Mark Lamport-Stokes)