Yamaguchi, a World Championships bronze medallist, overcame Ongbamrungphan 21-18, 21-18 to top Group B at Bali International Convention Center.

An Se-young of South Korea finished second courtesy of her earlier win against Ongbamrungphan in the group, which also included Singapore's Yeo Jia Min before she withdrew from the tournament.

Yamaguchi will take on Olympic silver medallist and current world champion PV Sindhu of India, who came second in Group A following a 21-12, 19-21, 21-14 defeat to Thailand's Pornpawee Chochuwong.

Victory for Chochuwong saw her claim first place in the group and her reward is a semi-final meeting with An.

Lee Zii Jia of Malaysia finished top of Group A in the men's tournament after beating India's Srikanth Kidambi 21-19, 21-14.

Defeat sent Kidambi crashing out of the event at the first hurdle.

Kunlavut Vitidsarn of Thailand claimed the last available place in the semi-finals following a 21-12, 20-22, 21-5 victory in his last group-stage match against France's Toma Junior Popov.

Jia will face Vitidsarn in the last four, while the other semi-final will be between Olympic champion and world number one Viktor Axelsen and India's Lakshya Sen.

Axelsen and Sen were drawn in the same group, where only one match was played after former world champion Kento Momota and Denmark's Rasmus Genke pulled out.

The Dane topped the group by virtue of his 21-15, 21-14 success against Sen.

It has led to a somewhat farcical scenario where they qualified for the semi-finals without having to win a match.