Top-ranked An, holder Yamaguchi reach badminton worlds semi-finals

South Korea's world number one An Se-young and defending champion Akane Yamaguchi registered strong wins to reach the semi-finals of the badminton world championships on Friday.

Olympic champion An beat China's Han Yue, who is ranked fifth in the world, 21-19, 21-12 at New Delhi's Indira Gandhi Indoor Stadium as she bids to win a second world crown.

An will face China's world number three Wang Zhiyi, who served past Line Christophersen of Denmark 21-10, 21-7 in the quarter-final clash to ensure herself a medal.

Japanese star Yamaguchi -- a three-time world champion who won the crown in Paris last year, beat Michelle Li of Canada 21-17, 21-10 in 28 minutes in a strong show of intent.

Yamaguchi will clash with Pornpawee Chochuwong, who got a walkover after Japan's Nozomi Okuhara withdrew from the contest due to a knee injury.

In men's singles, seventh-seeded Victor Lai of Canada had a tough outing against Denmark's Rasmus Gemke before he beat the unseeded player 21-19, 21-18 in 54 minutes.

World number two Kunlavut Vitidsarn fell to Alex Lanier of France 21-19, 16-21, 16-21.

Tenth-ranked Lanier made Kunlavut stretch with top smashes and returns and fought back after losing the opening game to make his first semi-final in the showpiece event.

Japan's 10th-seeded Kodai Naraoka stunned Denmark's world number four Anders Antonsen 21-19, 21-15 to advance to the final four.