DUBLIN, Ohio (AP) — Rory McIlroy hit into the water and into the trees. He even hit one shot twice.
Instead of seizing control Friday in the Memorial, he was 15 shots worse than his opening round and tumbled down the leaderboard at Muirfield Village.
McIlroy had to scramble for par on his final hole for a 6-over 78, turning a three-shot lead into a three-shot deficit among early starters in the second round.
Thorbjorn Olesen of Denmark had a 67 and was the clubhouse leader at 6-under 138.
McIlroy said the left knee he hurt on Thursday caused some pain on the driving range as he hit one ball after another. He said it didn't bother him on the golf course. The bigger problem was getting the ball in play. He didn't hit a fairway until his eighth hole (No. 17) and hit only four fairways.
"I didn't realize how thick the rough was until I got in it today," McIlroy said.
Olesen used the recipe that carried McIlroy in the first round — he found the fairway and holed putts, which works for everyone at Muirfield Village.
Adam Scott, who won Colonial last week in his debut at No. 1 in the world, kept it together with a 70 and was among those one shot behind. Jordan Spieth scrambled to a 72 in a round that could have been higher and was tied with McIlroy at 3-under 141.
Phil Mickelson finished a little bit better in his round of 70 and was still in the mix at 142.
McIlroy, a winner last week at Wentworth in the BMW PGA Championship, has been happy with his game except for the odd stretch of big numbers. That came back to haunt him again Friday in an ugly back nine that continued a most peculiar trend.
Starting his round on No. 10, he shot 43 on the back nine. It was his fourth straight PGA Tour event, and fifth out of his last six U.S. events, that he had a 40 or higher over nine holes. All of them have come in the second round.