The 26-year-old – winner of the event in 2012 – shared top spot with playing partner Spaniard Rafa Cabrera-Bello after an eight-under-par 64 at Gut Larchenhof.
After an outward nine of 33, Willett carded five birdies after the turn as he completed his round without dropping a shot, as did Cabrera-Bello. That gave the pair a two-stroke lead over seven players including Hartlepool’s Graeme Storm, Nuneaton’s Andy Sullivan and Northern Ireland’s Michael Hoey.
“It was good. It was one of those days when I rolled a few nice ones in,” said Willett, who did not play in yesterday’s pro-am because of a stiff neck.
Sullivan said an improvement in the mental side of his game was partly due to his round of 66. “My putting was a lot better and that always helps,” he said.
A total of 83 players finished the day under par, including home favourite Martin Kaymer on his first appearance since winning the US Open.
He is way back in a share of 65th, though, after a one-under 71 failed to really give the crowd much to cheer. Starting at the tenth, birdies in two holes were quickly undone by a double bogey at the 16th and another dropped shot at the 18th took him to the turn in one over.
Three successive birdies immediately got him back to two under but having hit his second into a greenside bunker at the 577-yard seventh he failed to get out of the trap from an awkward lie and bogeyed.
“It was a tough day for me on the greens,” said Kaymer.”