England's Robert Rock, the player who lost a play-off to local amateur Shane Lowry last year, opened the 3 Irish Open with a six-under-par 65 at Killarney on Thursday - and then was disqualified for signing for a wrong score.

33-year-old would have been tied for second place - level with Ireland's Damien McGrane and Australia's Richard Green - one stroke behind former Ryder Cup star David Howell.

McGrane out-scored his illustrious compatriots Padraig Harrington and Graeme McDowell by three and five shots respectively, while Darren Clarke shot 66, Rory McIlroy 67 and twice US Tour winner Justin Rose a desperately disappointing 74 that can only harm his Ryder Cup hopes.

Rock, seventh in The Open two weeks ago, 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.

Hoping to win the £415,000 first prize for a second successive time - Lowry was unable to claim the money - the Englishman said: "It's my fault. I checked it, but didn't see it and it's my job to do that."

He added: "I don't think I've been disqualified for anything before. I'd have preferred it to be after an 80!"