Bryson DeChambeau comfortably outscored tournament favourites Paul Casey and Patrick Reed to take the first-round lead at the Porsche European Open.
The American shot a six-under-par 66, which was three better than his English rival, while compatriot and Masters champion Reed was four strokes back courtesy of a birdie-birdie finish at the Green Eagle Golf Courses in Hamburg.
Three Frenchmen, Joel Stalter, Romain Wattel and Mike Lorenzo-Vera, and Germany's Benedict Staben, led the immediate challenge a shot further back.
"It's great to start out with six under par. I think it's one of my lowest rounds on the European Tour so I'm very pleased," the world number 23, playing in only his sixth regular tournament on the European Tour outside of the majors and WGC events, told europeantour.com.
"I haven't been hitting it my best so I'm still working on my game and it's starting to turn into some form.
"I'm missing in the right places and making some putts which is great. If you do that out here you're going to be up there."
Starting at the 10th he carded four birdies in his opening nine holes and - although he dropped a shot at the par-four third - he produced three further birdies in his last six holes, including a brilliant approach to the 517-yard last with his third from behind a tree.
World number 15 Casey briefly had a share of the lead at four under through nine holes, including an eagle on the par-five 18th, and a birdie at the last saw him bounce back from a double bogey at the short eighth.
That left him in a large group, including compatriot David Horsey and Scotland's David Drysdale, on three under.
Among those a shot better off were Welshman Bradley Dredge, and English pair Steven Brown and Oliver Fisher.
Reed, who appeared to be hampered by a knee injury, began with a birdie but struggled to find the fairway all afternoon finding a lot of the left rough - which cost him a shot on the par-five 11th.
Having fought to make pars on many holes he had a stroke of luck at the 17th when his birdie putt hit the back of the cup and dropped - otherwise it would have raced several feet past - and he followed that by picking up another shot at the last to close on two under.
Both Irish entrants struggled badly on the opening day and now have work to do to make the cut. Gavin Moynihan hit a five over par 77 while Ruaidhri Magee was even closer to the foot of the field after a seven over par 79.
