The four-time major winner felt he did well to battle to a one-over-par 73 – six behind co-leaders William McGirt and Mackenzie Hughes – in a round that included two double-bogeys on the tenth and 14th holes.

“What can I say, I was a little rusty out there,” he said. “I feel like I turned a 75 or a 76 into a 73, so it wasn't all bad. But I didn't hit enough fairways, didn't hit enough greens. It felt like I was scrambling all day. But I scrambled pretty well, and I birdied two of the last three holes to make it somewhat respectable.”

A slight cause for concern for McIlroy was stiffness in his back, which he believes has built up as a result of not hitting many balls over the past few weeks due to his wedding and honeymoon.

Read more - Rory McIlroy confirms $100m TaylorMade switch

“I haven't been able to practice as much as I wanted to the last few days and I've been very limited hitting golf balls as my back has got a little bit stiff again,” he explained.

“I guess it’s just from building it up, playing through and then not doing anything for three weeks and then coming back last weekend and hitting balls for four or five hours a day.

“I just aggravated that joint in my back again – the thing that sort of happened at the start of the season. I've sort of been trying to rest that and manage that, so I think that's why I'm a little bit rusty, as well.”