McDowell’s sole top-10 finish on the European Tour this season came back in February and he missed the cut when bidding for a third successive French Open title last week, a second round of 78 being his worst score in 32 rounds at Le Golf National.
The 35-year-old admitted he needed to “clear his mind” of thoughts about technique and looked to have succeeded with an opening 66 at Gullane, which was marred only by bogeys at the last two holes.
“It’s always disappointing to finish with a couple of bogeys but I played some good stuff today,” said McDowell, who carded four birdies in succession in a front nine of 30 and also birdied the 16th before three-putting the 17th and 18th.
“I drove the ball well and the putter was quite spicy the first 11 or 12 holes before cooling down, but I would have taken 66 before going out and I will take it now.”
McDowell revealed he and coach Pete Cowen had found the solution to his poor form by looking at videos of his swing from 2010, the year he won the US Open at Pebble Beach and holed the winning putt in the Ryder Cup at Celtic Manor.
“I’m trying to get back to basics and we have narrowed my stance and used my body to swing the club how I used to,” McDowell added.
“And it was nice to get back on a course that gives you a few opportunities in benign conditions. I just need a few low numbers to get my belief and confidence back and today will go a long way towards that.”
McDowell was by no means the only player to take advantage of the 7,133-yard par 70 composite course, with American pair Rickie Fowler and Matt Kuchar also finishing four under.
Denmark’s Thorbjorn Olesen had set the clubhouse target on seven under after a flawless 63, with England’s Matthew Nixon, Spain’s Adrian Otaegui and American Ryder Cup player Jimmy Walker on five under.
In a week dominated by Rory McIlroy missing his Open Championship defence due to an ankle injury suffered playing football, Olesen could sympathise with the world number one after injuring himself getting off a camel in Dubai last year.
“When I had to get down I pulled a muscle in my groin and it took a few weeks before I could walk properly again,” Olesen admitted with a smile.
The 25-year-old also discovered a tendon problem in his left hand over the winter but battled on for four events – missing the cut in the last three – before undergoing surgery at the start of February.
“It’s been a tough time but I keep working on the right things and hopefully it will come,” said Olesen, who lost a play-off for the Mauritius Open in May in his first event back after three months on the sidelines. “I showed today I can still shoot low rounds.
“I hit almost every green – only missing the 18th – and hit a lot of fairways and greens today, which was the key.”