Clarke was flawless on the front nine, hitting three birdies
-11 D Clarke (NI)
-8 J Edfors (Swe), D McGrane (Irl), C Schwartzel (RSA)
-7 D Drysdale (Sco), J Donaldson (Wal)
Darren Clarke fired a six-under-par 65 to move three shots clear and put a maiden win of the season within sight after round two of the Scottish Open.
The 37-year-old Ulsterman, who has not finished higher than third this season, shot seven birdies to build on his first-round 66 and move to 11-under.
That put him clear of South African Charl Schwartzel, Swede Johan Edfors and Irishman Damien McGrane in second.
Home favourite Colin Montgomerie ended on four under par back in 17th place.
The Scot roared out of the blocks with two birdies and an eagle in his first three holes, but failed to maintain the momentum as he carded a 66.
I hit it really nicely today and gave myself an awful lot of (birdie) chances
England's Lee Westwood and Ian Poulter lay on six-under and five-under respectively, while South Africans Ernie Els and Retief Goosen finished on three-under.
However, it was Clarke who made the most the ideal scoring conditions to build a good lead going into Saturday's third round.
"I hit it really nicely today and gave myself an awful lot of (birdie) chances," he said.
"I had a lot of putts from the 10 to 12 feet range for birdies and unfortunately missed a few. But, overall, six-under is pretty good."
Overnight leader David Drysdale ended the day in a tie for fifth on seven-under alongside Welshman Jamie Donaldson.