Datuk Lee Chong Wei had an easy passage to the semi-final of the Indonesia Open after Wang Zhengming retired in the second set of their quarter-final clash today.

Chong Wei, who is ranked second in the world, won the first set 21-16 before the Chinese retired at 9-2 in the match played at Istora Senayan in Jakarta.

The national champion will meet Ihsan Maulana Mustofa of Indonesia, who is ranked 29th in the world, in the semi-final match tomorrow.

Chong Wei is in line for his sixth Indonesia Open title as world number one, Chen Long is absent while his nemesis, Lin Dan lost in the second round.

He has collected 88,953 points, only 3,241 points behind Chen Long.

Winning the Indonesia Open will give Chong Wei another 11,000 points, making him the world number one player before the Rio Olympic Games starts.

The women's doubles, Vivian Hoo Kah Mun/ Woon Khe Wei, also did well by beating Anggia Shitta Awanda/Ni Ketut Mahadewi Istirani to enter the semi-final.

Hoo/Woon, who beat the Indonesian pair, 21-14, 21-19 will meet third seed, Tang Yuanting/Yu Yang of China.

The men's doubles, Goh V Shem/Tan Wee Kiong were shown the door by Chai Biao/Hong Wei of China, 18-21, 17-21.