The Northern Irishman, resuming on 3 under, made the most of still, dry conditions to shoot six birdies and an eagle 3 at the 12th in a bogey-free round on the defenseless links course at Castle Stuart on Friday.
Scottish pair Scott Jamieson and Peter Whiteford, who both carded 66s, were level with McDowell on 11 under.
“It’s nice to get the ‘low’ juices flowing,” said McDowell, the winner of the tournament in 2008 when it was held at the parkland Loch Lomond course. “We talked about someone doing a 60 this morning, it’s that easy.”
The leaders were a stroke clear of Spain’s Jose Manuel Lara (66) and two ahead of Argentina’s Angel Cabrera (64), Belgium’s Nicolas Colsaerts (66) and Scotland’s Paul Lawrie (64).
Sixth-ranked Phil Mickelson’s 67 put him on 4 under, leaving the American left-hander struggling to make the cut.
With the recently opened course in the Scottish Highlands yet to bare its teeth, the early starters made hay for a second straight day, with a smattering of birdies and eagles across the leaderboard. Rain was expected later Friday.
“I got to the course and realized conditions were easy and it was there for the taking,” said McDowell. “Like any links course, if there’s no wind the guys will take it apart.”
Last year’s US Open champion at Pebble Beach claimed the day’s joint best score with Cabrera and Lawrie, going to the turn in 30 after starting at the 10th and adding more birdies on the second and seventh holes.
“It’s probably going to take 20 under to win this week,” McDowell said.
Jamieson, a European Tour rookie, should have been the outright leader but messed up the eighth hole — his 17th — by fluffing a short chip and then three-putting, posting a double bogey to halt his charge.
He had started in irrepressible mood, making five straight birdies from the 11th and then an eagle on the long 18th.
Other high-profile players in contention were eighth-ranked Matt Kuchar of the United States and three-time major winner Padraig Harrington (both 8 under), with two-time Scottish Open champion Ernie Els of South Africa a further stroke adrift.
Matt Kuchar’s 66 ensured there will be American representation this weekend, but his fellow countrymen weren’t faring so well.
Mickelson came home in 32, which included an eagle on the long second hole, but may come up short like The Heritage winner Brandt Snedeker (1 under after a second-round 66) and Anthony Kang (3 under).
