Great Britain's Gail Emms and Nathan Robertson saw their Olympic dream come to an end after losing 21-19 21-12 to Lee Hyojung and Lee Yongdae.
The 2004 runners-up were outplayed in their quarter-final against the South Korean pair and could not repeat their heroics from the first round.
It is likely to be Emms's last Olympics as she indicated before the competition she was planning to retire, aged 31.
"It's gutting because I know we can play better," said a tearful Emms.
606: DEBATE
Men's number one seed Lin Dan comfortably overcame a tricky encounter with Denmark's Peter Hoeeg Gade in the singles.
The home favourite triumphed 21-13 20-16 to book a semi-final meeting with fellow countryman Chen Jin on Friday.
South Korea's Lee Hyunil beat China's number three seed, Bao Chunlai, 23-21, 21-11 in a heated clash, where a controversial umpiring desicion halted play for more than five minutes in the first game.
The world number 10 will now face Malaysia's Lee Chong Wei, who is aiming to win his country's first ever gold medal in any sport.
Emms and Robertson, who bravely battled back from six points down in the final game of their opening match to beat the Chinese second seeds, got off to a slow start and failed to lead at any point during the first game.
At one point they trailed 20-16, but rallied and recovered to 20-19 before a fantastic return on the Emms serve from the impressive Yongdae sealed the first game for the Koreans.
Excellent low serving from the Koreans proved key as Emms and Robertson failed to cause any real danger on the return.
But after falling 8-3 behind in the second game, the Brits won five straight points to take the lead.
It proved to be a brief stay of execution, however, as the Koreans again took control forcing both Emms and Robertson into numerous errors.
After leading 10-9 they soon found themselves trailing 20-11 and the match ended as Robertson could only guide a tame forehand wide.
"If it was our last tournament then we've had a fantastic time together," he said.
"The dream ending for us just didn't happen. It's been an amazing partnership and it's a shame it has to come to an end, but we have some fantastic memories to take away with us."
Emms is adamant that Robertson, also 31, must play on without her.
"He's going to miss me so much, but Nathan is an amazing talent," she said.
"He's like the Roger Federer of badminton, he's so naturally talented and gifted.
"He can help to bring up the next generation. He can be a great mixed doubles partner for them. Any young girls should watch his racket skills and be inspired by him."
After beating Emms and Robertso South Koreans will now play Indonesia's number three seeds Flandy Limpele and Vita Marissa who defeated Kamilla Rytter Juhl and Thomas Laybourn of Denmark 21-17 15-21 21-17.
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