US PGA Championship: Rory McIlroy soldiers on after hurting his wrist to remain in the hunt

The US Open champion confirmed he will have an MRI scan after hurting the tendon and also his right forearm when striking an iron against a tree root on the third hole. After completing his round McIlroy said: "I'm going to go and get an MRI scan now and see there's no damage done to it."

He explained at his press conference: "It was dangerous.

"I thought maybe the tree root was a foot in front of the ball and thought if I could make contact with the ball and let the club go I could get away with it.

"In hindsight I would have been better to chip out sideways and still get a five. But it was a shot where I thought if I took it on and pulled it off it could have saved me a shot.

"I've obviously gone through impact. I held on to the club too long and jarred my right wrist and right forearm.

"It was obviously very painful after that."

The 22-year-old's drive down the 475-yard third finished against a tree root, but he tried a full-blooded second rather than just chipping out onto the fairway.

McIlroy's club came flying out of his hands and he immediately felt his wrist.

The world No 4 was handed an ice pack to apply and then given a lengthly examination on the fifth green.

McIlroy, having bogeyed the hole where the incident happened, even got up and down from a bunker on the long fifth and then sank a 20-foot putt for another birdie at the next. Another bogey came on the eighth before his arm was bandaged up and he did well to par the ninth for an outward level par 35.

McIlroy had even more bandaging applied before starting the back nine, then spoke to a physio again after a bad drive into the trees on the 10th. Again he decided to carry on and after chipping out onto the 18th fairway hit his third over the tall pines to 15 feet and made the par putt.

He drove badly on the long 12th as well, this time left, but was on in three and holed from 15 feet for birdie and remarkably went to one under and joint 18th. As McIlroy pressed on, escaping with a par at the 13th despite going in two bunkers, questions were being asked about whether the physio gave advice over the playing of his second shot on the 12th.

The incident had been brought to the attention of tournament director Kerry Haigh. After pars at 13 and 14, McIlroy made his third bogey at 15 to drop back to level par but responded immediately with a birdie at the 16th only to drop another shot at 17 before finishing off with a par.

Meanwhile, PGA Championship organisers were given a scare on the eve of the tournament when the edges of two greens at Atlanta Athletic Club suffered "minor damage" after being mown by greenkeeping staff.

The affected greens were the par-4 14th and par-3 17th but both were repaired before the start of yesterday's opening round."This damage is believed to be the result of a significant rise in the dew point at approximately 7pm which caused the brushes on the mowers on those greens to stick in the grass and damage the turf," the statement read.

The areas of repaired turf on both holes will be played as 'ground under repair' for the entire tournament, giving players free relief on any putt where the line is affected, the PGA of America said.

Ken Mangum, director of golf courses and grounds at Atlanta Athletic Club, said he was mortified by the two incidents. "Last night we felt like our hearts had been ripped out," Mangum said. "Something occurred that I've never seen before and I can only speculate what happened.

"Nothing mechanical, no operator error. It's a little mystery to me why it happened."