China secured finals berths in mixed doubles and women's doubles at the badminton World Championships on Friday, as four pairs set up all-Chinese semifinals in the two events in which Chinese took two gold medals out of five last year.

The two semifinals feature defending champions, mixed doubles duo Zheng Siwei and Huang Yaqiong, as well as women's doubles pair Cheng Qingchen and Jia Yifan.

Top seeds Zheng and Huang downed South Korean duo Kim Won-ho and Jeong Na-eun 21-10, 21-6 in only 27 minutes to reach the semifinal round.

"Our tactic was very clear today, which was to get them moving. We did not fully use the space in our last encounter, " said Zheng after the win.

The three-time world champions suffered a loss to the South Korean pair earlier this year at the Singapore Open.

Zheng and Huang will next face World Championship debutants Jiang Bangzhen and Wei Yaxin, who beat local favorites Mathias Christiansen and Alexandra Boje 21-16, 21-18.

The women's doubles top seeds later on Friday emerged victorious after a three-set match against Japanese duo Nami Matsuyama and Chiharu Shida 21-15, 16-21, 21-16.

"We were thrilled the moment we won. This is our sixth World Championships trip, and we don't know how many more times we can play this tournament. This isn't like the first time, where we knew there were more to come. We really want to win this one," said Chen after the match.

Chen and Jia, who are also three-time winners at the event, will next face compatriots Zhang Shuxian and Zheng Yu, who came back from one set down to take a 17-21, 21-17, 21-19 victory from Malaysia's Pearly Tan and Thinaah Muralitharan.

"We told ourselves there's no leeway anymore in the second set. We had to push ourselves to unleash all the energy," said Zheng.

In the men's doubles quarterfinal, third-seeded Chinese pair Liang Weikeng and Wang Chang beat Indonesia's Muhammad Shohibul Fikri and Bagas Maulana 21-18, 15-21, 21-14.

(With input from Xinhua)