Rory McIlroy headed straight to the driving range after dropping off the pace during the BMW Championship's second round in St Louis.

The Masters champion opened with a six-under-par round to share the lead, but managed to improve his score by only a single stroke on Friday with a 69.

"I feel like conditions were pretty similar to yesterday," McIlroy told the Golf Channel.

"The wind was coming out of a different direction, but still very scorable. The greens are soft, maybe the ball’s got a little bit more run out on the fairways, but you’ll still see guys shooting pretty good scores today.

"I didn’t quite hit it as good as I did yesterday, so probably an afternoon on the range for me.

"I’m proud of how I just hung in there. A lot of good par putts on the back nine, especially. The only bogey I had was with a mistake on the par-five eighth hole, but I made some really good par saves coming in and that sort of kept me in it."

McIlroy’s underwhelming round came after Bryson DeChambeau hit back at the Northern Irishman after he questioned the value that the American and Jon Rahm had brought to LIV Golf, amid the breakaway league’s struggles.

DeChambeau said: "I think we just have a bit of a responsibility to continue to show this. If it works, it works; awesome. If it doesn’t, we’ll figure things out."

He added: "Time will move on, and I would say that time heals things. I hope people can see that we actually bring value to the game of golf. My wish is that people give us one more shot and be open minded."

American JJ Spaun looked on course to dominate the second round after reaching 11 under at the turn.

Three bogeys on the back nine slowed his advance, but two birdies, including at the 18th, set the early clubhouse target on 10 under.

World number one Scottie Scheffler, two over after a first-round 72, bogeyed the first but bounced back with five back-nine birdies to remain contending at three under.