Three dropped shots around the turn have cost Padraig Harrington the lead but the Dubliner remains well-placed in the 90th US PGA Championship at Oakland Hills.

The Open champion had birdied his opening three holes to join move straight to the head of the leaderboard, one ahead of clubhouse leaders Robert Karlsson and Jeev Milkha Singh.

But bogeys at the seventh and ninth, and a subsequent six the par five 12th, nullified Harrington's early progress and left him on level par and a share of 14th place. Harrington added a further bogey and birdie before play was suspended due to the stormy weather in the Detroit area.

Karlsson, from Sweden, took advantage of ideal morning conditions to card a two-under-par 68, finishing level with Indian Jeev Milkha Singh.

Sergio Garcia enjoyed an encouraging start to his campaign, coming home in 69 blows while world number two Phil Mickelson, tournament favourite in the absence of the injured Tiger Woods, and fellow American Anthony Kim opened with 70s.

Darren Clarke, like Harrington among the later starters, is currently two-over through 13 holes while Graeme McDowell finished on four-over.

Karlsson, the only player to have posted top-10 finishes in the first three majors this year, was delighted after rattling in six birdies in 10 holes from the second.

"I played really well on the front nine and got the putter going," the Swede told reporters after teeing off at the par-four first in the second group of the day.

"The greens were absolutely perfect so once I rolled a couple in I tried to just keep going."

World number one Woods, who claimed last year's title by two shots in Tulsa, Oklahoma, is sidelined for the rest of 2008 after having reconstructive knee surgery following his US Open triumph in June.