His first-round scoring average of just under 68 leads the PGA Tour but his second-round average is almost five shots worse, with rounds of 63 and 78 in the Memorial Tournament the worst example of a worrying trend and part of a run of shooting 40 or more for nine holes in four straight events in America.

McIlroy needed another 40 shots to cover the back nine in Aberdeen and had to save par from greenside bunkers on the 17th and 18th to make sure of being here for the weekend.

“It’s been the case all year. I’ve got off to great starts and fell away but I am still in the tournament and I can go out in the morning and try to get some of those shots back,” the 25-year-old said.

“You are having to talk about it (his Friday performances) so it’s in your mind and I am maybe putting more pressure on myself to shoot a good score. It’s another Friday out of the way, thank God, and I can go on to the weekend. I shot 68 on the Friday at the US Open so hopefully next week will be the same.”

Asked if he was shell-shocked, McIlroy added: “Yeah, because when I went to the gym in the morning the wind didn’t seem as strong as it is now so I wasn’t expecting this. Everything was tougher.”

In contrast, Ryder Cup team-mate Justin Rose went from woeful on Wednesday to title contender today, carding a 68 to finish five under par and just one off the clubhouse lead shared by Scotland’s Marc Warren and Swede Kristoffer Broberg.

Rose, who won the Quicken Loans National at Congressional a fortnight ago, said: “I came here on Wednesday and felt absolutely horrendous. It was like I had lost my game somewhere over the Atlantic. But the last couple of days I have been finding my feet again and that’s part of the reason for playing this week ahead of Hoylake.

“It was great to see the course in a completely opposite wind. The par fives are playing very easy on the front nine and there are some tough par fours on the back nine. I did well to hang on to my score on the back nine and made a few good six or seven-footers coming in.”

Warren squandered a three-shot lead with four to play in the 2012 Scottish Open at Castle Stuart and admitted it would be a “romantic tale” if he could make amends on Sunday.

“It’s a massive week and anyone would love to win, but being Scottish it would be that much more special,” Warren said after birdies on the 16th and 18th gave him a 69. “What happened two years ago was tough to take at the time but it was good experience and hopefully it will stand me in good stead.

“The course is tough enough anyway, never mind playing the back nine into this wind. After bogeys on the 14th and 15th I said to my caddie let’s try to have a strong finish but to finish three-three-three was beyond my wildest dreams.”

Six-time major winner Nick Faldo had threatened to produce something special when he birdied the fourth and fifth and holed from 40 feet for an eagle on the sixth, but the 56-year-old dropped four shots in five holes from the eighth and eventually carded a second consecutive 73 to finish four over par.

“I played nicely on the easy holes downwind, then I made a couple of bad swings and it just scared me,” said Faldo, who spends most of his time as a television analyst in America but will also compete at Hoylake next week. “I didn’t know what to do for a while.

“I was going nicely, inside the cut line, but then I made a mess of it. Simple as that. I’m here on curiousity, that’s my bottom line. I have a really good day job. I’m just curious to see how I can play this game.”