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.