Mikael Lundberg described it as “not a complete shock” after finding himself top of the Lyoness Open powered by Greenfinity leaderboard at the halfway stage.
The Swede made the most of ideal morning conditions to reach nine under par and boost his chances of a first European Tour victory in six years.
Lundberg added a 68 to his opening 67 at Diamond Country Club to finish one shot ahead of playing partner Lee Slattery.
“I hit a lot of good shots early on and managed to make some putts, so that got my confidence up,” said Lundberg.
“It’s a nice feeling when you get your distance control right with your wedges, because it takes a lot of pressure on your putting.
“It got tougher and tougher the longer the round went on, because the course got really firm and fast towards the end, so whilst it may look and feel easy, it never is.
“I’ve been doing some great work with my new coach, Neil Jordan, over the last few weeks, and my game is feeling a lot more solid as a result. So whilst I didn’t maybe expect to play this well here, it’s not a complete shock to me either.”
Lundberg had shared the overnight lead with England's Adam Gee, but wasted little time in moving clear of the field when play resumed on Friday.
The 40 year old, whose previous wins came in the Russian Open in 2005 and 2008, parred the first two holes but then spun his approach to a couple of feet at the third to begin a run of four straight birdies and move into a four shot lead.
Lundberg, whose last top-ten finish was almost two years ago and who had to regain his card for the third successive year at the Qualifying School, dropped his first shot of the day after a clumsy chip on the eighth.
And although he saved par after missing the green on the tenth, his lead was down to two shots as Slattery holed from 15 feet for birdie on the same hole.
A birdie from 30 feet on the 12th saw Lundberg extend his lead, although he then missed from a fraction of the distance on the next after a superb approach and was unable to find any further birdies on the closing stretch.
Slattery carded an eagle, five birdies and one bogey to return an impressive 66, with Paraguay's Fabrizio Zanotti third on seven under, Korea's Sihwan Kim six under after a 68 and defending champion Joost Luiten another stroke back following a flawless 67.
“It was great,” said Slattery, whose only European Tour win came in Spain three years ago.
“I got off to a decent start again today, and I was off and running. I made some good up and downs at important times, which kept the momentum going.
“It’s a tricky course, there are potential disasters on every hole so you definitely can’t afford to get ahead of yourself.
“It’s quite old school golf where you’ve got to control your ball and put it in the right places. That suits me, so I’m enjoying it.”
Luiten was delighted with a round that kept his victory hopes alive, and a successful defence would provide a welcome boost to his Ryder Cup hopes.
"I'm very happy with five under," the 28 year old Dutchman said. "I made some nice saves for par and that's what you have to do around this course. You are going to be out of position sometimes and you have to play smart and try to save par.
"I am right back in there and that was the goal today, to try to make some ground on the leaders. We will see what happens and we have still 36 holes to go."
Local favourite and 2011 winner Bernd Wiesberger lies three under following a second round 70, but Miguel Angel Jimenez had three double bogeys in five holes as a 75 left him one over for the week.
The best recovery of the day had come from Australian Brett Rumford, who played his first four holes in five over par but the remaining 14 in seven under to return a second round of 70 and finish one under par.