Badminton world number one Viktor Axelsen swiftly routed Taiwan's Chou Tien-chen on Friday, storming into the Indonesia Open semi-finals, but women's world number one Akane Yamaguchi crashed out.

Danish ace Axelsen is the defending Indonesia Open champion, and he played with an aura of invincibility in Jakarta, racing to a quarter-final victory over the world number eight 21-5, 21-19 in 39 minutes.

"I think first set, I played really, really well. I came out really strong. I'm a little bit disappointed about my level in the second game," he told reporters.

"But all in all, I'm really happy to be in the semi-final."

He will face India's H.S. Prannoy in the last four.

Japan's Yamaguchi had no such luck, falling to Thailand's Ratchanok Intanon in a three-game thriller.

They were evenly matched in the first two games with scores of 18-21, 25-23, until the Thai player romped to victory in the decider 21-16.

"I think my opponent played better today. She was better prepared and she can play the game that suits this hall," she told reporters.

South Korea's An Se-young, the women's world number two, survived a scare in a three-set win against China's He Bing Jiao despite rolling her ankle and needing medical attention after the match.

The 21-year-old rising star finished strong against the fifth seed, leaving her with too much to do in the final game and winning 21-18, 19-21, 21-11 to secure her semi-final place.

"I followed what my coach said. My coach told me to be more focused for the third game," she said.

"I didn't want to easily give up, despite the injury. I have to win... I have no word for giving up."

She will face China's Chen Yu Fei in the semis.

Three-time world champion Carolina Marin also beat last year's champion Tai Tzu-ying of Taiwan 21-18, 21-13 to secure her place in the last four.

Men's world number two and hometown hero Anthony Sinisuka Ginting beat compatriot Jonatan Christie, ranked 7th in the world, in two games in front of a raucous crowd.

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