Xander Schauffele fired a seven-under-par 64 to claim a three-shot first-round lead, with Day’s 68 leaving Australia’s former world No.1 in a seven-way share of fifth.

Day opened eagle-birdie to be three under through two holes, but rued cooling off as two bogeys offset two more birdies at Quail Hollow.

“Got off to a really nice start. A little scrappy on the back side, I would say,” he said.

“Just missed a couple of easy up-and-downs.”

Day still finished as the leading Australian, two strokes ahead of Cam Davis at one under, with Adam Scott carding an even-par 71.

With the course playing considerably tougher than in previous years, Day said the tournament will prove the perfect tune-up for next week’s PGA Championship, which he won in 2015 and finished second a year later.

“You would rather this test than something where it’s super-easy and it’s super-receptive,” he said.

“We don’t know what we’re going to get next week in Valhalla. Last time I played there we had a boatload of rain and it was soft.

“But if we do get good weather, they’re going to firm the greens up pretty good.

“So it’s kind of nice to be able to come from a week like this where the course set-up is really nice, the conditions are tremendous and then getting into a major.

“It kind of feels like a mini major here this week.”

Schauffele enjoys a three-shot advantage over Northern Ireland’s world No.2 Rory McIlroy, a three-time winner of the tournament, fellow American Collin Morikawa and Sweden’s Alex Noren.

– Darren Walton, with Reuters