Rory McIlroy vowed to shake off his US Open hangover and battle his way back into the Irish Open mix at Fota Island today.

The Holywood ace crashed to a disappointing three over 74  and is now in danger of a missing cut for the second year on the trot.

But he refused to blame jetlag or the late arrival of his clubs for his bad start and promised to open up with all his firepower and try and repeat the 62 he shot in the Pro-Am.

McIlroy said: "Hopefully this is my bad round out of the way. All the par fives out here are reachable for me and here's a few short par fours and there's plenty of chances to score.

"I'll try to get it back to four or five under for tomorrow and go from there.

"Last week was a prime example of when you're just grinding for pars and you sort of get used to that in a way.

"Even when I was a couple over today, I didn't feel like it was that bad. But three-over here is a lot worse than three-over at Pinehurst."

Graeme McDowell and Michael Hoey flew the home flag with three under 68s to finish the day just four shots adrift of flying Finn Mikko Ilonen.

The former West of Ireland winner posted a course record 64 to lead by two shots from Swedish pair Robert Karlsson and Magnus A Carlsson and Germany’s Marcel Siem on seven under.

McIlroy's presence at the weekend is crucial if the European Tour is to build on yesterday's 16,000 crowd.

But with Padraig Harrington firing a solid 69 before being joined by amateur ace Gavin Moynihan and gutsy Dubliner Peter Lawrie on two under, there's hope for an Irish challenge.

Shane Lowry could only manage a level par 71 but the Clara star insists he'll be going out with all guns blazing early today.

Convinced that nobody will run away from the field, Lowry said: "I think something in the early teens under par will do the business this week.

"The rough is very juicy out there and the fairways are quite tight. I don't see anyone running away on 20 under this week, that's for sure."