McIlroy's shot at the third flew wildly to the right and came down, amid warning shouts, right next to Japanese player Toshinori Muto's caddie Toru Oda.

The 23-year-old had two reasons for relief - no injuries and just about avoiding the rough - but he still bogeyed the hole and had, by the 18th, left himself with a real mountain to climb at Royal Lytham.

McIlroy said his second round 75 was just something he would need to improve on.

"I feel like if I can maybe get it back (tomorrow) to where I was at the start of the day, I'd still have a great chance."

The world number two also confirmed he had made sure 16-year-old Jason Blue (who was injured on Thursday) was put up in a hotel and given some cash and a signed glove.

"I thought it was the least I could do when he's got a massive gash in the side of his head," McIlroy said.

"I put him and his mate up for the night and actually tried to get them into the hotel for a couple more nights, but they were just fully booked."

It was just one of those days where I couldn't quite get on my game and struggled to get any sort of momentum.

Rory McIlroy

Meanwhile fellow countryman Graeme McDowell boosted his chances of a second major title after adding a second round of 69 to his opening 67 to finish four under par.

The Portrush man is six shots behind halfway leader Brandt Snedeker.

But he described parts of the course at Royal Lytham as almost "unplayable" after heavy overnight rain.

"A few of those bunkers out there are a little bit of a question mark," McDowell said on Friday. "But we're lucky that we're playing. The golf course is on the edge of unplayable.

"A few of these bunkers need to be taken out of play. Hopefully they can get them dried out overnight. The golf course has remained unbelievably dry considering how much rain we've had. The bunkers are a little dodgy in some places, unfortunately."

Defending champion Darren Clarke exited the tournament early after adding a second round of 71 to his opening 76 for a seven-over-par total of 147.

It has been an honour and privilege to be Open champion. It is a huge honour to have my name on the Claret Jug and they will be memories that I cherish forever.

Darren Clarke

"I'm disappointed, I would have liked to come here and put up a good score in defence," said the 43-year-old.

"Tee to green was okay, I just had a very cold putter again. It's not been very good for a long time. The damage was done yesterday but I gave myself plenty of chances to make it up today."

He said he enjoyed the warm reception of the crowds at Royal Lytham.

"The roar coming down the last was fantastic. The crowd were wonderful to me last year and have been to me all year round. It is a pity I didn't give them anything to shout about."

British Amateur Champion Alan Dunbar, from Portrush, also missed the cut - exiting the Open on six over after rounds of 75 and 71.

Twice champion Padraig Harrington stands two over, following a 72 that included bogeys at three of the final four holes for an inward 40.