Paul Casey snatched the first-round lead with a classy round of 66 at the Porsche European Open.
The Englishman spends most of the year on the PGA Tour but has returned to Europe for this week's event - and said his performance in gusty conditions felt even better than the score suggested.
Austrian Matthias Schwab, who has hit a purple patch of form in recent weeks with consecutive top-10 finishes at the Czech Masters and European Masters, carded a 67 to sit alone in second place at the Green Eagle club near Hamburg.
Casey's last win on the European Tour came at the KLM Open in 2014, although in the United States he has triumphed twice at the Valspar Championship, retaining the title in he won in 2018 earlier this year.
He said of his performance on Thursday: "It was a really good round of golf. There were a few putts that slid by but that is such a difficult golf course. I can't explain how difficult that golf course is.
"I was happy with the patience I was showing and the quality of the ball-striking, and here I stand even happier because the score doesn't do it justice as that is one of the finest rounds I've played this year."
"The score was great. I couldn't have hoped for better. I'm happy to be under par, never mind six."
Scotland's Robert MacIntyre, German Max Rottluff and England's Ben Stow share third place on four under.
A star US trio failed to get to grips with the course on day one, however, as Xander Schauffele posted a one-over 73, with Patrick Reed and Matt Kuchar both a shot further back.
Former teenage wonder Matteo Manassero, now 26 and struggling on tour, had an even worse day, with triple-bogey eights at 16 and 18 seeing him sign for an 81.