USPGA Championship: British Open champion Pádraig Harrington was happy to put a frustrating opening round behind him at the 90th US PGA Championship and still remain in contention at Oakland Hills.

Harrington carded a one-over-par 71 to sit just three shots behind first round co-leaders Robert Karlsson and Jeev Milkha Singh as the Dubliner heads into today's second round.

He had made a flying start with a hat-trick of birdies only for four bogeys between the seventh and 13th holes to derail his promising start.

Harrington bounced back with a birdie at the 14th to return to level par as play was suspended by rain and the threat of lightning for 83 minutes.

When play resumed, Harrington dropped another shot at the long par-three 17th but rescued par at 18 with a superb approach shot from the semi-rough to inches from the hole.

"I was trying to calm down," Harrington said before marching straight to the putting green after signing his card.

"It felt like I played a lot better than 71. I really struggled on the greens and I had a number of putts that the hole lipped out on, so it made me feel like I was putting a lot worse than I was maybe.

"Then it even got a little bit into my longer game towards the end of the round as I was getting a bit more frustrated."

Now Harrington has to convince himself that he emerged from his day's work still in with a chance of securing back-to-back major victories.

"The score is good," he added. "And I have to sit down and get that into my head tonight and look that it's only the first round.

"This is all you want in the first round; you want to keep yourself in there. It's all about staying patient for the first three days and I need to get my head around that.

"I just need to get a bit more confidence back in my putting and that sort of gets into your game, as well."

Graeme McDowell was one of the early starters and opened with a four-over 74, one better than Darren Clarke's 75.