Andy Roddick’s hopes of reaching a second successive Wimbledon final were ended as he was stunned 6-4 6-7 (3-7) 6-7 (4-7) 9-7 by unseeded Yen-Hsun Lu.
The world number 82 produced a superb performance and held off a typically spirited comeback from the fifth seed.
Yu led 3-0 in the fourth set tie-break but Roddick hit back to level the tie.
Roddick had a break point to lead 5-4 in the fifth but Yu saved it and went on to become Asia’s first Grand Slam quarter-finalist for 15 years.
His performance emulated that of Japan’s Shuzo Matsuoka, who reached the last eight at Wimbledon in 1995 before losing to Pete Sampras.
Yu has never before progressed beyond the third round of a Grand Slam and had never made it past the second round at SW19 in six appearances.
He was facing a formidable task in taking on the American, whose Wimbledon record boasts three appearances in the final, one semi-final and one quarter-final.
Roddick took the first set with the only break point out on Court Two but Yu took the next two sets, neither of which featured a break point, on tie-breaks to edge ahead in the match.
There were also no break points in the fourth set which again needed a tie-break to settle it and after Roddick put a backhand long and Yu held his serve twice, he seemed on the verge of a famous victory.
However nerves may then have played a part as after a Roddick ace, Lu put two forehands long to see his lead disappear. The fifth seed then moved ahead and an ace put him 5-4 up.
Roddick earned a set point when Lu netted another forehand and the American then produced his 11th ace of the set and 29th of the match to level the contest at two sets apiece.
The fifth set was understandably tight but Roddick had his chance to move ahead in the ninth game only for Lu to save a break point and go on to hold.
The pressure was now on the 27-year-old as every service game was to keep him alive in the match.
It finally told in the 16th game as Lu played a superb passing shot on his first match point to wrap up a memorable triumph.