World number one Jon Rahm was among the players battling miserable conditions on day three of the 105th US PGA Championship at Oak Hill.
Heavy rain greeted the early starters and was forecast to continue for much of the day, adding to the challenge on a course where just nine players were under par at the halfway stage.
Rahm made the cut with a shot to spare after rounds of 76 and 68, but the Masters champion bogeyed his first two holes on Saturday to slip back to six over par.
Former Ryder Cup star Thomas Pieters was having a much happier time, the Belgian making four birdies in the first five holes to improve to one over par and move inside the top 20.
Scottie Scheffler, Corey Conners and Viktor Hovland shared the halfway lead on five under, with Bryson DeChambeau and Justin Suh two shots behind.
McIlroy continued to struggle with his long game over the first two days, but was pleasantly surprised to still find himself in contention for a third US PGA title and first major since 2014.
“I think with how terribly I’ve felt over the ball, the fact I am only five back… I’m not saying it could be up there with one of my best performances but when I holed that (birdie) putt on the last I thought ‘I can’t believe I’m only five back’,” McIlroy said after a second round of 69.
“If I can get the ball in play off the tee I’ll have a shot and at this point I might just tee it high and bomb it everywhere.
“I may as well just swing it hard and go for it.”