Top seed Chou Tien Chen came back from a game down to beat home favourite Maxime Moreels in the second round of the Bitburger Open.
The shuttler from Chinese Taipei was staring down the barrel of an upset defeat but recovered superbly to record a 14-21 21-7 21-10 victory after 42 minutes.
Also advancing was second seed Tommy Sugiarto of Indonesia, who beat Kim Bruun 21-9 21-15.
German third seed Marc Zwiebler and fourth seed Hans Kristian Vittinghus also won on the day, Zwiebler beating Toby Penty 15-21 21-18 21-19 and Vittinghus edging Misha Zilberman 15-21 21-3 21-14.
Fifth seed Rajiv Ouseph of England was up against Petr Koukal, and completed a 21-13 21-15 win.
Malaysian 14th seed Wei Feng Chong was also in action, defeating Lukas Schmidt 21-11 21-18.