David Howell leads after the first round of the 3 Irish Open at the Killarney Golf & Fishing Club with a seven-under-par 64.
Australian Robert Green, twice a winner on The European Tour, hit a six under par round of 65 to move to sit second, after birdies on the 16th and 18th.
Green said that the Kerry course was helpful to his game.
"I'm not known as one of the longer hitters out on Tour, and when you get a golf course that feels like the sort of golf course that I grew up on, length wise, putting surfaces, it's nice.
"It's nice to play a golf course like that again."
Ireland's Damien McGrane joined him in second place, with his own 66, after birdies on 1 and 7, then on 10, 12, 14, and 16.
Darren Clarke is one of eight players tied fourth after shooting 66's.
Clarke, who will be one of Europe's vice-captains at The Ryder Cup, birdied the third, seventh and ninth. The Ulsterman produced a 12 foot putt to add another on the 11th, then birdied the 16th in his bogey-free round.
Clarke has been chosen as one of three non-playing vice-captains by the Europe captain, Colin Montgomerie, but he still has time to make the team for Celtic Manor.
"I will play if I qualify and I think Monty will want me to," Clarke said. "We spoke at length about it and Monty's said he wants me there one way or another."
Tournament favourite Rory McIlroy had an erratic round, but with three birdies in the last five holes, finished on four under par.
McIlroy had four birdies in his opening seven holes, but bogeys on the eighth, ninth, 11th and 12th saw him drop down the leaderboard before his late recovery.
Robert Rock has been disqualified after signing for a wrong score. The 33-year-old opened with a six-under-par 66 but did not spot that his card had him down for a par on the 14th and birdie at the next instead of the other way around.
"It's my fault," he said. "I checked it, but didn't see it and it's my job to do that. I don't think I've been disqualified for anything before. I'd have preferred it to be after an 80!"