Lin Dan of China competes during the quarterfinal against Marc Zwiebler of Germany at 2015 Sudirman Cup BWF World Mixed Team Championships in Dongguan, South China's Guangdong province, May 14, 2015. [Photo/Xinhua]

DONGGUAN -- Favorites China were never in a spot of bother against Germany on Thursday, winning 3-0 without dropping a game and booking a semifinal berth at the Sudirman Cup.

It was the second victory over the same opponents in this tournament for China as the defending champions also whitewashed Germany in their group match.

Zhang Nan/Zhao Yunle, the world number one, won the opening mixed doubles over Michael Fuchs/Birgit Michels 21-9, 21-11. It was Zhang Nan's first match since he withdrew from the Asian Championships due to injury last month.

"He has recovered and wants to play more to find his form," said Zhang's partner and also girlfriend Zhao Yunlei.

"As he also has men's doubles later tonight, I try to help us win as quickly as possible. It's a big test for us before the Rio Olympics as we both has one more event to play besides mixed doubles," she added.

Lin Dan made it 2-0 in men's singles over Marc Zwiebler 21-12, 21-15. They changed shirts with each other after the game, arousing loud cheers from a packed arena at the Dongguan Sports Center in Guangdong province.

"Actually, it is a little bit boring to play with the same opponent," said Lin Dan.

Fu Haifeng/Zhang Nan sealed the tie in men's doubles with a breezing victory over Michael Fuchs/Peter Kaesbauer 21-15, 21-17.

London Olympic champion Li Xuerui and the newly-assembled pair Yu Yang/Tang Yuanting had no need to play as in knockout stage the match finishes when either side wins three games.

China, who have won the fifth Sudirman Cup, will meet either Indonesia or Chinese Taipei in the semifinals.