Home favourite Alex Noren claimed a three shot halfway lead at the Nordea Masters with a Bro Hof Slott Course record - although the latter did not last long.
The 29 year old signed for a six under par 66 in his native Stockholm to reach 11 under par.
Five birdies in a spectacular outward 31 took the two-time European Tour winner clear of overnight co-leaders Jaco Van Zyl and amateur Robert Karlsson, and he struck his tee shot to three feet on the par three 11th to complete the scoring in a bogey free round.
India’s Shiv Kapur is Noren’s nearest challenger after reaching eight under courtesy of a 66, which matched Noren’s course record within an hour of it being set.
But in one of the last groups of the day Korean Jin Jeong birdied three of his last four for a seven under 65.
“I played probably the best I’ve ever played,” said Saab Wales Open champion Noren. "It’s just been great, everything has been going better.
“I don’t think I’ve ever done that on this course and I’ve played here a lot,” he added when asked about keeping a bogey off his card.
“It really helps playing this course alot, I know what lines there are and I know when to step back.”
Kapur is yet to win on The European Tour despite this being his sixth season, but he started his round with a hattrick of birdies from the 11th, holed from 20 feet on the 15th and, after three more gains and two bogeys, birdied his final hole of the day to put himself firmly in contention heading into the weekend.
Big-hitting American Bubba Watson saw his eagle putt creep in at the ninth and birdied four in a row from the 12th, but The Ryder Cup star was still not satisfied with his 67.
“I struggled on the front nine,” he said, after moving into a share of third place on six under. “Made a couple of dumb mistakes - three bogeys. Hit one in the water today - it could be better. I’m in a good position though, I’ve got to keep making birdies and hopefully not make any mistakes.
“I knew I was going to have a lot of short irons if I hit it over bunkers. There’s five par fives so you know I love that.”
Van Zyl joined Watson after a one under 71, with Jeong, England’s Anthony Wall, Australian Scott Hend and Karlsson a shot further back - although this time it was the former European Number One on the leaderboard rather than his amateur namesake, who could only manage a 75.
Starting his second round on the tenth, 41 year old Karlsson reeled off four consecutive birdies from the 15th to turn in a three under par 33.
The 11-time European Tour winner had a chance to join Watson in third after playing his third shot off the rocks to six feet at the par five ninth, but he missed the birdie putt and had to settle for a 70.
“It’s always a fairly high scoring golf course,” he said. “At 15 I had long two-putt for birdie, 16 hit a good six iron to a couple of feet, then holed two long putts.”
Asked about seeing his name top of the leaderboard before teeing off on Thursday, he added: “It was quite interesting not having started and leading a tournament, so it was quite funny! Robert Karlsson four under and he’s on the range!”
Hend is yet to record a top-20 finish on The European Tour this season, but found the lengthy Bro Hof Slott course to his liking as he added a 70 to his opening 69.
“It’s been a while since I’ve played golf, so nice to come out and play solid so far,” he said. “Hopefully the weekend will continue that way.
“I need to produce - I haven’t produced so far this year, it’s been a bit of a tough year. I feel like I’m playing good but not producing any results so hopefully that will turn around.”