It’s a measure of the level of Louis Oosthuizen’s game right now that he doubled his bogey tally on Saturday in the 149^th Open Championship as he dropped shots twice in the third round, but he still managed to look as if he is on his way to winning a second major championship.

He carded a one-under-par 69 at Royal St George’s on the day fans and players refer to as ‘moving day’, and took his score through 54 holes to 12-under-par. That gave him a one-stroke edge over Collin Morikawa of the United States, and, crucially, put him three clear of Jordan Spieth who has consistently looked as if he could mount a challenge strong enough to win him a second Claret Jug.

“I was 13-under at one stage,” he said. “Probably a good back nine could have taken me to to 14 or 15. I made a few bad swings there in the middle of the round and that put me in some awkward positions and I ended up making two bogeys. I had four-iron in on 14 and I made a horrible swing, ended up making a par. I did have a lot of opportunities to go two or three better, but that’s what this golf course can do to you.”

Oosthuizen started the third round looking as steady as he has throughout the championship so far, and he racked up six successive pars to start his round. He burned the hole on a couple of occasions, and could have had a few birdies under his belt by the time he actually made his first on the par-five seventh. He picked up another shot on the ninth.

But then the pressure he had endured through the first two rounds and much of the third, to say nothing of the pressure he must feel as the whole golfing world dissects his unenviable record of six runner-up finishes in majors, finally told. He pulled what should have been a relatively straightforward tee shot on the par-three 11^th and was unable to get up and down for par. Then, on the 13^th, his approach was also pulled left and getting down in two from the thick rough was just not possible.

That saw him drop back to level-par for his third round, and 11-under for the tournament, together with Spieth. And, when his playing partner Morikawa made birdie on the par-five 14^th, there were three major champions all on 11-under.

He nearly compounded things with a poor shot on the 15^th. “I was worked up about 45 minutes ago when I hit that five-iron on 15,” he said. “I just kept really calm because it was a shot that I should have backed off probably, taken the six-iron. But it was the wrong choice I made, and I hate making wrong decisions. I don’t mind hitting bad shots, but wrong decisions are something that I have control over. I was a bit upset there, but got myself together quickly and made a great up-and-down.”

Oosthuizen found his mojo off the tee again on the 16^th as he hit it to eight feet. He rolled in his birdie putt as Spieth was faltering with consecutive bogeys on 17 and 18, and Morikawa was unable to pick up any more shots coming home. That gave Oosthuizen breathing room going into the final round.

While his play has suggested he won’t need it – he was a driving machine for almost all the holes in the third round, and there were enough near-misses with his putter to suggest that, with a little luck, he could have been four-under instead of just one – breathing room down the stretch of an Open Championship is a good thing.

“I’m very excited, it is a great position,” he said. “I need to play well tomorrow and see if I can get rid of those loose swings.

“You need to believe that you can lift the trophy as well and if you think about it beforehand that you might win this championship, I think that’s great, and you have to believe you can do it. Finishing second isn’t great, so I will play my heart out tomorrow and see if I can lift the Claret Jug again.”