Jonathan Thomson fired the lowest round of his European Tour career to set the clubhouse target on day one of the Made in Denmark.
The Englishman's 64 at Silkeborg Ry Golf Club would have been a course record had preferred lies not been in place and moved him to eight under, two clear of local favourite Lucas Bjerregaard, New Zealander Josh Geary, Australian Brett Rumford and American Hunter Stewart.
Belgian Thomas Detry, Welshman Jamie Donaldson, Spaniard Scott Fernandez and English pair Sam Horsfield and Richard McEvoy were then at five under - with Donaldson birdieing six of his last eight holes on a wet but calm day in Silkeborg.
In the race for the final automatic qualifying place for the Ryder Cup Team, local hero Thorbjørn Olesen knows that a tie for seventh with one other or better will secure his place at Le Golf National.
He opened with a one over par 73 but two late birdies on the seventh and eighth greatly increased his chances of making the weekend.
For him to be overtaken this week, Matthew Fitzpatrick or Eddie Pepperell must lift the trophy and they were both among the day's later starters.
Thomson's story is a remarkable one: having overcome leukemia as a child he earned his debut European Tour campaign at the Qualifying School last year, in the process becoming the tallest player in Tour history at six foot nine and a half inches.
After a shaky start to his Tour career, he has made four of his last five cuts as he battles to retain his playing privileges at 216th on the Race to Dubai Rankings presented by Rolex.
Fellow Q-School graduates Geary and Horsfield were among the very early leaders at five under, with Geary making a gain on the third and four in a row from the fifth, while Horsfield picked up birdies on the third, fifth, 11th, 12th and 13th.
Geary made further gains on the tenth and 11th but Horsfield hit back on the 16th before Geary drove the par four 12th for a birdie and a two-shot lead.
A Horsfield bogey at the 17th extended the advantage to three but Thomson set about cutting it, adding a birdie at the 11th to earlier gains on the third, fourth, fifth, seventh and ninth.
Geary then bogeyed the 13th and with Thomson picking up a shot on the 12th he was in a share of the lead.
Thomson went bogey-birdie from the 13th but made a gain on the 16th and when Geary dropped a shot at the last, the advantage was two shots.
Bjerregaard picked up shots on the 11th, 12th and 17th to turn in 33 and then hit an incredible second into the third, spinning his ball a long way back off the fringe for another gain.
A monster putt would follow on the next before an excellent bunker shot on the eighth set up a sixth birdie of the day.
Rumford eagled the 12th and birdied the 13th and 14th to turn in 32. He holed from ten feet on the fourth and birdied the par five next after getting on in two but three-putted the seventh before making another gain on the eighth.
Stewart - playing just his third European Tour event after two invites with a top ten last week - started with five birdies from the tenth but bogeyed the third and fourth before bouncing back with gains on the fifth, seventh and eighth.
Thomas Pieters won this event en route to earning a Captain's Pick for the 2016 Ryder Cup and - playing alongside Olesen and Vice Captain Lee Westwood - he carded an opening 69 to sit five off the lead.
