Joakim Lagergren took the early lead at the Made in Denmark as Thomas Pieters continued his quest to impress Ryder Cup Captain Darren Clarke at Himmerland Golf & Spa Resort.
Pieters cannot now qualify automatically for the European Team that will go to Hazeltine in September but followed his fourth at the Olympic Men's Golf Competition with a second-placed finish at last week's D+D REAL Czech Masters.
Another good week in Farsø would keep him in Clarke's thoughts ahead of the Captain's picks being announced on August 30, and the Belgian was just one shot off the lead early in the first round.
That was held by Swede Lagrgren, who picked up birdies on the 12th, 14th, 15th, 16th, second and third in his first 12 holes to get to six under.
Nino Bertasio and Bradley Dredge were alongside Pieters at five under with birdies in plentiful supply on day one.
Pieters started on the back nine and made four birdies in six holes before dropping a shot on the 16th and then making back-to-back gains to turn in 30.
Welshman Dredge opened with a bogey on the tenth but then made six gains in his next eight holes - including five in a row from the 14th.
Bertasio had a mixed bag in his first 12 holes, with a double-bogey on the seventh cancelling out an eagle on the fourth for the Italian, while he also made five birdies.
Nicolai Tinning - son of two-time European winner Steen - was making his European Tour debut and was in a group at three under alongside English pair Ben Evans and Chris Paisley, Welshman Jamie Donaldson and American David Lipsky.
Swede Robert Karlsson gave the crowds on Himmerland Hill an early cheer as he made a hole-in-one at the signature 16th hole, sinking a pitching wedge from 124 yards for the 33rd ace of the season.
