Title holder Chen Hong of China was stretched all the way by unseeded Malaysian Lee Tsuen Seng in a gripping quarter-final clash at the All England badminton championships on Friday.
Seng saved three match-points, finally yielding after 89 minutes with Chen winning 15-4, 16-17, 15-11.
Chen, the top seed and world number one, now faces 27-year-old Muhammad Roslin Hashim of Malaysia, who knocked out fourth seed Kenneth Jonassen of Denmark 15-4, 15-13.
In a rare slice of badminton history, Hashim's younger brother Hafiz, 20, is also through to the semis after accounting for compatriot Yong Hock Kin 15-6, 15-10.
He now meets China's Chen Yu, who sprang a 4-15, 15-10, 15-11 surprise to oust fellow countryman Xia Xuanze, seeded three. Chen Hong is the only seeded player remaining in the men's singles.