Mistaken identity? Zach Johnson is used to it. “I’ve been called ‘Dustin’ many times … but I doubt Dustin has been called ‘Zach’ that many times,” he said with a self-deprecating grin.

Despite his haul of 12 tour titles, a plunder which includes two majors, there’s still a sense that when folk see the name Johnson on a leaderboard, the assumption is that it will be Dustin not Zach.

Undervalued, underestimated, under the radar? Perhaps, but Zach Johnson is also well under-par here at Carnoustie. His sturdy 67 for a six-under aggregate had him handily placed at halfway as this hardy perennial of the Open reaffirmed his fondness for the game’s oldest major.

The 42-year-old has put together a fine body of work in this championship, including a win three years ago, but, not for the first time, there wasn’t much fanfare about him in the build- up. It’s almost as if he mounts some kind of clandestine assault under the cover of darkness.

After missing his first three cuts in the Open, Johnson finished 20th in the 2007 championship here at Carnoustie. Since then, he’s made the weekend every year and, in addition to that victory at St Andrews in 2015, has four top-15s in the last six Opens.

So is he bothered about the lack of attention? Not in the slightest. “I’m wholeheartedly used to it,” said the former Masters champion.

“Maybe I’m just overly conservative and boring? And that’s perfectly fine. I just like to compete. It doesn’t matter where it is or what it is. Just give me an opportunity.”

Johnson certainly seized his opportunity yesterday with a purposeful push that bolstered his title tilt.

A ropey tee-shot on the first led to a bogey, but the response was swift and three birdies in four holes from the third got him moving.

After a four on the par-5 14th, Johnson finished with a flourish and trundled in a raking putt of 40-feet for a birdie on the last. Not many do that.

“I think my game lends itself to this championship because my style can play here,” said Johnson, who is known more for his game inside 100 yards than his ability to unleash long distance rockets off the tee.

“Everybody says you’ve got to hit it low, knock down, punch it in. And you do. You’ve got to use the ground. You’ve got to know where to land it. But you’ve got to hit it high, hit it left, hit it right. You’ve got to hold it. You’ve got to turn it, use the wind. You’ve got to do everything.

“I’m not suggesting that someone doesn’t have a higher reverence for the Claret Jug than me . . . but I’d argue with them.”

As a 40-something, Johnson is an elder resident in the house-sharing he does at events with a posse that includes the likes of Justin Thomas, Rickie Fowler and the reigning Open champion Jordan Spieth.

A couple of years ago, the group made a pact that whoever wins the Claret Jug has to fork out for the private jet which whisks them back across the Atlantic. How the other half live eh?

“I didn’t pay last year,” said Johnson. “But I’d be happy to fork out this time.”

If he picks up a second Claret Jug this weekend, Johnson certainly won’t be flying under the radar.