The fourth seed, who won men’s team bronze at the 2014 Asian Games in Incheon, came from behind against his Danish opponent to record an impressive 16-21, 21-14, 21-17 win.

Awaiting Chou in tomorrow’s final is number two seed Lin Dan of China after the two-time Olympic champion breezed to a 21-12, 21-13 victory at the expense of South Korea’s Son Wan Ho.

There were no surprises in the women’s singles draw as number two seed Li Xuerui, the reigning Olympic champion, beat Japan’s Nozomi Okuhara 15-21, 21-13, 21-13 to set up an all-Chinese final with Wang Shixian, who overcame Akane Yamaguchi of Japan 21-13, 19-21, 21-19.

Arguably the biggest shocks of the day came in the women’s doubles as the two highest-ranked pairings both crashed out against unseeded opposition in the penultimate round.

Top seeded Indonesians Nitya Krishinda Maheswari and Greysia Polii lost 21-16, 22-24, 19-21 at the hands of Thailand’s Puttita Supajirakul and Sapsiree Taerattanachai.

This was followed by a 9-21, 21-19, 18-21 defeat for number two seeds Misaki Matsutomo and Ayaka Takahashi of Japan against China’s Huang Yaqiong and Tang Jinhua.

In the men’s doubles, top seeds Lee Yong Dae and Yoo Yeon Seong overcame Japan’s Hiroyuki Endo and Kenichi Hayakawa 21-19, 21-14 to progress to the final where they will face fellow South Koreans Ko Sung-hyun and Shin Baek-cheol.

Ko and Shin, the number six seeds, defeated Russia’s Vladimir Ivanov and Ivan Sozonov 21-18, 18-21, 23-21.

The mixed doubles final will also be an all-South Korean affair after top seeds Ko and Kim Ha-na and fifth seeds Shin and Chae Yoo-jung successfully came through their semi-final encounters.

Ko and Kim beat compatriots Choi Sol-gyu and Eom Hye-won 18-21, 21-13, 21-17, while Shin and Chae defeated Poland's Robert Mateusiak and Nadiezda Zieba 21-14, 17-21, 21-12.

The German Open is a BWF Gold Grand Prix event.