Sweden's Johan Edfors, twice a winner already this season, sprinkled nine birdies in a six-under-par 65 to share the lead with Britain's David Drysdale in the Scottish Open first round.
Edfors and Drysdale took advantage of calm and sunny conditions at picturesque Loch Lomond to move one stroke ahead of Ireland's Darren Clarke and Miles Tunnicliff of England.
Edfors (30) who won the TCL Classic and British Masters earlier this year, made a blistering start with four birdies in the first five holes.
He dropped strokes at the sixth, 12th and 16th but made further inroads on par at the eighth, 10th, 13th, 15th and 18th.
Drysdale, backed by his home crowd, was consistency personified.
Starting his round at the 10th, the 31-year-old from Edinburgh picked up six birdies in an error-free round.
Earlier, Clarke explained why Sundays were proving less than fun days for him.
"I am close to playing okay but mentally I am not quite there," the 37-year-old said.
"I am making a few silly mistakes, especially come Sunday. My Sunday score average this year is very, very high, which is totally out of character for me."
Last week's European Open at the K Club typified Clarke's season.
He went into the final round two shots off the pace but a closing four-over-par 76 ruined his chances and victory went instead to Stephen Dodd.
"Doddy played really nicely but I didn't perform at all again," said Clarke. "Unfortunately there have been quite a few Sundays this year when I have done that."
Former US Open champion Hale Irwin (61) finished his round in brilliant fashion with five successive birdies to shoot a three-under 68.
Fellow American Fred Couples pulled out with back trouble before the start of the round.
Scot Sam Torrance, making a record-breaking 700th tour appearance, carded a 74 while South Africans Retief Goosen and Ernie Els returned matching 70s. Reuters
