No 3 seed Antonsen needed just 49 minutes to see off Tsuneyama in Osaka and set up a final four showdown with Japan’s Kenta Nishimoto.

Antonsen said he had “not many expectations” for this week after losing to Nishimoto in the first round of last week’s World Championships in Tokyo, but the 25-year-old said he was “improving, slowly”.

“I didn’t make that many mistakes and I was quite explosive – I think I played a good match,” said Antonsen, who is returning from a three-month injury lay-off.

“I just wanted to have fun and get back to my game and I’m working on that every single day. I’m not there yet but these three matches have been very good.”

China’s Shi Yuqi will face Taiwan’s Chou Tien Chen in tomorrow’s other semifinal.

Shi thrashed Thailand’s Kantaphon Wangcharoen 21-6, 21-13, while Chou outlasted India’s HS Prannoy 21-17, 15-21, 22-20.

Denmark’s Viktor Axelsen, who won the world title last week, pulled out on the eve of the Japan Open.

On the women’s side, Japan’s world champion Akane Yamaguchi advanced with a 21-18, 21-18 win over Thailand’s Pornpawee Chochuwong.

Spain’s Carolina Marin fell in the quarterfinals for the second straight week, losing 21-18, 13-21, 21-17 to South Korean No 3 seed An Se-young.

“I’m a bit disappointed that I lost today but I know I am on my way back,” said Marin, who returned to the court in May following a knee injury that sidelined her for a year.

“I know that I am improving. I believe in myself so this is the most important thing for me right now.”

Yamaguchi will play China’s Chen Yufei in tomorrow’s semifinals, while An will face Taiwanese No 2 seed Tai Tzu-ying.