JAKARTA: Top seed and defending champion Chen Long survived a mammoth second-game tussle to advance to the semi-finals of the badminton world championships with a 21-18 30-29 victory over Denmark's Viktor Axelson on Friday.

The Chinese world number one needed 65 minutes to subdue his seventh-seeded opponent as his equivalent in the women's draw, Spaniard Carolina Marin, enjoyed her best performance of the week on the adjacent court to advance to the last four.

In the evening matches, hopes of a dream semi-final between veteran arch-rivals Lin Dan and Malaysia's Lee Chong Wei were dashed when the Chinese five-times world champion was beaten in straight sets by Danish second seed Jan O Jorgensen.

Lee, who has topped the world rankings for almost 300 weeks but is on the comeback trail following an eight-month doping ban, remained on course for a maiden global crown with a routine 21-12 21-18 victory over Hong Kong's Hu Yun.

Jorgensen's victory was equally emphatic as the European champion cruised to a 21-12 21-15 win over the fifth seed to set up a last-four encounter against the in-form Lee, who has lost just one match, to Chen, since returning from his ban in May.

Chen has yet to drop a game in his three matches at the Istora Senayan arena but the lanky 26-year-old needed all his supreme court coverage skills to retain that spotless record and improve his head-to-head statistic to 5-0 against the Dane.

Axelson started the stronger of the pair and forged two-point leads several times in the first game but found himself behind when Chen's five-point surge overturned an 18-16 deficit to allow him to take the opener.

The second game was even closer once Axelson had erased an early three-point deficit and the players traded the lead all the way to its conclusion, with Chen saving seven game points before clinching victory on his sixth match point.