COPENHAGEN - Denmark's Viktor Axelsen was stunned by China's Chen Long in the semifinal of the badminton Denmark Open 2019 on Saturday.

One set apiece, with the big Dane leading, Chen's seemingly pedestrian style of play did not change significantly, but his points certainly did and his points tally suddenly surged forward to win the game.

So unexpected was the triumph that it felt as though Axelsen had managed to grasp defeat from the jaws of victory.

Chen's remarkable win 12-21, 21-14, 21-19 set him up for an encounter with world number one Kento Momota in an all Asian final on Sunday

In the women's doubles, Chen Qingchen and Jia Yifan beat Japanese pair Yuki Fukushima and Sayaka Hirota 18-21, 21-17, 21-18 and will face South Korea's Ha Na Baek and Kyung Eun Jung in Sunday's final.

In the mixed doubles, China's Wang Yilyu/Huang Dongping defeated South Korean opponents Seung Jae-seo and YuJung Chae 21-15, 15-21, 21-11.

Wang Yilyu and Huang Dongping will meet Indonesia's Praveen Jordan and Melati Daeva Oktavianti in the final.

Meanwhile, world number one women's singles player Tai Tzu Ying of Chinese Taipei was a dominant presence over the court during her semifinal clash with Chen Yufei, who ranked third.

Chen was running out of time and needed to launch a counteroffensive to win the second set and remain in the match. Instead, a catastrophic twist of her right ankle forced Chen into early retirement and gifted Tai the win 21-12, 14-11 and a place in the final on Sunday to face Japan's Nazomi Okuhara.

In the men's doubles, Marcus Fernaldi Gideon and Kevin Sanjaya Sukamuljo will meet Mohammad Ahsan and Hendra Setiawan in what will be an all Indonesian final.