German veteran Alex Cejka posted a superb eight-under-par 64 to take a one-shot lead after the first round of the Thailand Golf Championship.
Early starter Justin Rose had looked finishing at the head of the leaderboard after a bogey-free 65, but Cejka overhauled the US Open champion with his eighth birdie of the day at the signature par-three 17th island hole.
Rose ended up in a tie for second alongside local player Arnond Vongvanij, while India's Gaganjeet Bhullar was alone in fourth on six-under, with Swede Daniel Chopra a further shot adrift.
A host of big names are well positioned with defending champion Charl Schwartzel and Spain's Sergio Garcia four back after opening 68s, while American duo Bubba Watson and Rickie Fowler stand at two-under, along with Henrik Stenson.
The last of Cejka's four European Tour wins came over a decade ago in France and, while delighted by his excellent start, the 43-year-old insisted he was not looking too far ahead.
"I hit the ball very well today," he stated. "The greens roll perfect. I took a couple of big chances and made birdies.
"I am very pleased, I played really well today. It is a great feeling. I hope my form will continue like this.
"There are still three rounds to go and there are a lot of great players in the field. Anything can happen."
For his part, Rose missed only one green in regulation during a virtually flawless ball-striking display and admitted, having got over a very early alarm call, he had enjoyed some ideal conditions at the Amata Spring Country Club on the outskirts of Bangkok.
"It was an early alarm call this morning at 4.30," said the Englishman. "(I) didn't enjoy that part but once I got out here to the golf course it was a perfect morning for golf, nice and cool to start with.
"Our group all birdied the 10th hole and I felt like we got off to a really nice start. It was a perfect morning to play golf, and the type of morning you wanted to capitalise on.
"My putting felt really sharp, I was reading the greens well. The key is to hit the fairway and follow it up with good irons."