BIRMINGHAM, England - Five times champion Lin Dan of China fought off tenacious challenge from teammate Tian Houwei to reach the last eight at the All-England Open championships here on Thursday.
Lin, also twice Olympic gold winner and five times world champion, beat the 23-year-old Tian 21-15, 21-19.
"Nobody wants to meet teammates at such an early stage," the 31-year-old Lin said. "Houwei played smartly today, but maybe he has put himself under too much pressure."
Trailing 3-6 in the second game, Tian scored six points in a row for a 9-6 lead with powerful smashes. The scoreline was levelled several times until Tian made it 18-18. But Lin, nicknamed Super Dan in China, gave no chance to his teammate, winning 21-19 and reaching the quarterfinals.
Top seed Chen Long, last year's beaten finalist, crushed Hsu Jen Hao of Chinese Taipei 21-7, 21-9.
Fifth-seeded Lin will next take on Japan's Kento Momota while Chen faces Chou Tien Chen of Chinese Taipei.
In the women's competition, China's top seed Li Xuerui suffered a surprise defeat to less known compatriot Sun Yun.
Li, the winner in 2012, was beaten 21-13, 21-13 by the 21-year-old Sun.
"I have tried my best today, but I have not entirely recovered from my foot injury yet, I only started training again about two weeks ago," Li said.
Second seed Wang Shixian of China beat Bae Yeon Ju of South Korea 21-12, 13-21, 21-9 and her teammate Wang Yihan saw off Japan's Minatsu Mitani 21-23, 21-6, 21-16.
Sixth seed Carolina Marin of Spain, last year's surprise winner at the world championships, also advanced to the last eight with a win over Porntip Buranaprasertuk of Thailand 21-10, 21-16.