Rory McIlroy’s carefree 66 at the Open shows a player in control of his game

God but Rory McIlroy makes the game look easy when he’s in the mood. If it hadn’t been for the grandstands, and the tens of thousands of fans, you’d never have guessed what was at stake as he strolled around the Old Course in the opening round of the Open.

Up, down and around the slopes and hollows, all the drives down the middle, a chip there, a flop there, each lag putt right up to the hole, each short one into it, the ball only ever one stroke away from where he wanted it to be. He made a carefree 66, with seven birdies, and just the one dropped shot.

He was paired with Collin Morikawa, who made 72, and Xander Schauffele, who made 69, but it felt at times like they were only there to help put the way McIlroy was playing into proper perspective, like those little diagrammatic humans included in the picture to give it a sense of scale. Morikawa is the reigning champion golfer of the year, Schauffele has just won the Travellers and the Scottish Open back-to-back and is in better form than any man on the Tour, but they struggled to keep up. “It was awesome,” Morikawa said. “That’s what I need the next three days.”

On the par-five 5th, McIlroy’s drive smacked into an old boundary stone. It cost him 30 yards or so. The first he knew about it was when someone pointed it out. “I think I still hit it past the other two.” He still picked up a birdie too.

He had made his first of the day on the opening hole, with a 30ft putt that set his morning up like ham and eggs in bed. There was a third at the 6th and a fourth at the 7th. But it was the par he made at the 8th that he picked out as one of his favourite moments of the round. “I hit a good putt for birdie on the 8th hole, but hit it three feet by. I wasn’t really that comfortable with the second putt, but I stepped up there, committed to it, and holed a nice putt.”

None of this was as straightforward as he was making it seem. “There’s pivotal moments in the round, they could be little things like that putt on the 8th, they’re the little parts that test you.” Especially when the play was as slow-going as it was here, where the heavy traffic on the big double-greens led to the rounds taking the best part of six hours.

It meant players spent a lot of time leaning on their clubs in between using them and had to snap in and out of focus when they finally stepped up to address the situation they had been stewing on for the last few minutes. McIlroy managed it perfectly. He made his one bad mistake at the 13th, when he tried to get too cute with a chip from behind a greenside bunker and whizzed the ball a good 60ft beyond the hole, but he corrected it by rolling the putt right up to the cup for a tap-in bogey.

At the 614-yard 14th, he unleashed such a mighty drive that he was able to play a wedge into the green. It went over the back and he had to get up and down for his birdie. At the 17th there was another of those pivotal little moments, when he found himself 85 yards out but with such a tricky lie that he was worried he was going to thin the ball into downtown St Andrews. “I chipped a little gap wedge down there and I pulled it. But I played the right shot so that if I did miss it, it wasn’t in too bad of a spot but I could then get it up-and-down.”

At that point, he’d already accepted in his head that “four was going to be a good score”. Which about sums him up at the moment, he looks like a man who knows exactly what he’s trying to do and how he wants to do it.

It hasn’t always been that way. McIlroy has subscribed to a lot of different theories in the eight years since he won his last major, has tried muscling up, tinkering with his swing, taken on a couple of different gurus, even delved into self-help. Now, he says, he’s “taken ownership of everything again” and stopped listening to all the different people he’d been employing to tell him “how to play”.

After all, he said, “I’m pretty good at this game”. He sure is. He sounds like a man who’s in control. The only question now is whether he can keep hold of it through to Sunday evening.