The first-round leader at the Aberdeen Asset Management Scottish Open tumbled down the leaderboard with a second-round 78 at Royal Aberdeen, including a back-nine 40.
Worldwide, McIlroy has played his first rounds in 51 under par this year but 9 over in the second round.
"It's always sort of being brought up, it's on your mind. Maybe put myself under even more pressure to get off to a decent start and shoot a good score," said McIlroy, who then quipped. "Another Friday out of the way, thank God."
For the second time this year, McIlroy followed a round of 64 or better with a 78. He shot 63 during the first round at the Memorial and then had 78. His first-round scoring average this year is 68.15 but just 72.23 on Fridays.
Among the places where McIlroy has shot 40 or more for nine holes this year are Doral, Augusta National, Quail Hollow, TPC Sawgrass and Muirfield Village.
"I'd be much happier standing here after a couple of 71s [even par], but that's not the case," McIlroy said. "It hasn't been the case all year. I get off to a good start and then I just fall away. But I'm still in the tournament, and I can go out in the morning and try and get a few of those shots back that I lost today.
"I need to try and hold it together somewhat. I'm still in the golf tournament, and I need to try and make some birdies early and get back in it."
McIlroy dropped to even-par 142, 6 strokes behind tournament leaders Marc Warren, Kristoffer Broberg and Ricardo Gonzalez and into a tie for 34th. McIlroy had just one birdie with six bogeys and a double-bogey. He also needed 35 putts.
Just 17 of 150 players shooting below 70 on the par-71 Royal Aberdeen links course.
Justin Rose signed for a 68 and is alone in fourth place, a shot behind.
He was not alone in his frustration. Defending champion Phil Mickelson shot 73 to drop to 1 under and 7 strokes back.
"It was tough," Mickelson said. "But it was fun to have these conditions. You have to try different shots. I thought I actually played pretty well but you make one bad swing, and you are going to pay a penalty. And I made a couple of those. You really have to focus on each shot.
"I'm a little concerned about having to expend a lot of energy with the Open [Championship] coming up. But it's also good preparation."
McIlroy concurred, and hopes to get back on track Saturday with the Open Championship looming at Royal Liverpool next week.
"It's a grind out there, but at the end of the day it's a great way to prepare for next week," McIlroy said. "But I don't want to just prepare for next week. I want to try and get myself back into this golf tournament and win. I'm playing well enough. There are signs my game is there, but I need to tidy up a few bits and pieces."