Jack Nicklaus criticised Rory McIlroy for a lack of concentration as the 88th Masters belatedly got under way at Augusta National.

Overnight rain and the threat of thunderstorms saw the start of play pushed back from 8am to 1030am, with honorary starters Nicklaus, Gary Player and Tom Watson kicking off proceedings 20 minutes earlier by hitting tee shots on the first before retiring to the clubhouse.

The trio then gave a lengthy press conference before Nicklaus joined “Live from the Masters” on the Golf Channel and discussed why McIlroy had yet to win a green jacket to complete a career grand slam.

“I only have one criticism of Rory,” 18-time major winner Nicklaus said.

“You have to concentrate 100 per cent of the time. For some reason, Rory always has a little bit of a lapse somewhere around the tournament. He’ll find a double bogey or triple bogey that sneaks in there.

“I don’t know how he does it or why he does it, but it happens. And I wish that wouldn’t happen.”

During the earlier press conference Nicklaus said he believed McIlroy would win the Masters at some point, but pointed out that Watson and Arnold Palmer both missed out on a career grand slam after failing to win the US PGA.

“I mean, is Tom Watson good enough to win the Grand Slam? Absolutely,” Nicklaus said.

“Was Arnold Palmer good enough to win the Grand Slam? Absolutely. Is Rory McIlroy good enough to win the Grand Slam, absolutely, but they have got to do it, and they all know that.

“Do I think Rory will win here? Yeah. He could win this year. He could win next year. He’s just too talented not to. But then again, they (Watson and Palmer) were too talented not to win those, too. You just never know.”

McIlroy made a slow start to his 10th bid to complete the grand slam, covering his first six holes in one over par while playing partner and pre-tournament favourite Scottie Scheffler picked up two birdies on the same stretch.

Defending champion Jon Rahm was one under par after seven holes, with New Zealand’s Ryan Fox setting the early pace on five under thanks to birdies on the first three holes and an eagle on the par-five eighth.

The weather delay meant the first round would not be completed on schedule on Thursday, with the last group of Dustin Johnson, Collin Morikawa and Tommy Fleetwood not teeing off until 1630 local time.