In a final round delayed by more than four hours due to bad weather, Pieters birdied the last three holes for a closing 65 to finish 17 under par and a shot ahead of overnight leader Bradley Dredge, of Wales, who birdied the last to secure his second runner-up finish of the season.
Sweden’s Joakim Lagergren stood on the 18th tee in a tie for the lead with playing partner Pieters, but lost his ball after a wayward drive and the resulting triple-bogey seven dropped him into fifth place behind David Lipsky and Adrian Otaegui.
Pieters was fourth in the Olympics and second in the defence of his Czech Masters title last week to force his name into the frame for one of European captain Clarke’s three wild cards.
After carding 62 71 while playing alongside the Northern Irishman in the first two rounds, the 24-year-old could not have done anything more to earn his place on the team for Hazeltine next month.
Lee Westwood and Martin Kaymer – who finished joint sixth at Himmerland Golf and Spa Resort – have long been favourites to secure two of the wild cards as Clarke looks for experience alongside the five rookies among the nine automatic qualifiers.
But that leaves Clarke with what appears to be a tough choice between Pieters and Scotland’s Russell Knox, who won the WGC-HSBC Champions last November when not a European Tour member and added the Travelers Championship earlier this month.
Pieters said: “I would say so. I’ve done all I can and we’ll just wait and see.”
Woodsome Hall’s Chris Hanson continues to impress on his debut season on the European Tour, claiming a third top-20 placing in 16 events, only three of which have seen him miss the cut.
He shot 69 69 69 71 to tie for 18th and his €21,360 winnings liift him to 113 on the Race to Dubai.