Korean star K J Choi had an eagle and four birdies in the space of seven holes to take over the lead at the Nordea Scandinavian Masters.
Choi burst to ten under par, while first round joint-leader Louis Oosthuizen went in the water for a double bogey five on the short 17th at Bro Hof Slott.
Open Championship winner Oosthuizen suddenly went from two ahead to five behind as a result.
The 27 year old South African, trying to become the first player in European Tour history to win a week after lifting The Claret Jug, resumed with birdies on two of his first three holes.
As a result golf's newest Major Champion dropped back to five under and alongside Australian Richard Green in joint second place. Green was among the day's later starters.
American Dustin Johnson, the man who had a closing 82 after leading the US Open Championship by three at Pebble Beach last month, was the other player to record a 67 on day one, but he managed only 38 for the front nine to be three under.
Johnson, on course for a Ryder Cup debut at The Celtic Manor Resort in October, had further birdies at the 13th and 16th, but they were offset by bogeys on the tenth, 11th, long 15th and 164 yard 17th.
