Great Britain's Susan Egelstaff saw her London 2012 badminton campaign come to an end after a battling defeat to Japan's Sayaka Sato.
The Scot benefited from some dubious line calls as she took early control but Sato, who initially seemed rattled after complaining about decisions, recovered to win 18-21 21-16 21-12.
Egelstaff had an opportunity to push for victory in the second game but, at 16-15 down, her opponent produced a fine drop shot and did not look back as she closed out a place in the last 16. It was still a valiant effort from world number 38 Egelstaff against a player ranked 22 places above her, the Briton having recovered from a serious leg injury to compete.
Egelstaff broke away in the first game with a run of six successive points but Sato complained increasingly furiously over two line calls. For the second one, at least, it seemed she had a point after an Egelstaff shot that appeared to land just out was called in.
Perhaps still bothered by the incidents, she made a number of mistakes and Egelstaff brought up five game points. The Glaswegian lost three of them but converted at the fourth attempt to establish an early advantage.
Sato was on the wrong end of another controversial line call early in the second game. Although she complained again, this time Sato maintained her composure to open up a six-point lead.
Egelstaff refused to bow and forced Sato to start making errors again and clawed back within one. Sato's body language suggested she felt nothing was going her way but mistakes on Egelstaff's part then allowed her to level the match. The third game was tense but Sato began to look the more convincing player and found more winners as she eventually powered away.
Britain's men's singles hope Rajiv Ouseph also saw his Olympic bid come to an end as Guatemala's Kevin Cordon came from behind to beat him 2-21 21-17 21-19 in a three-game thriller.
Chris Adcock and Imogen Bankier, who could not progress in the mixed doubles, were unable to secure a consolation win against world number ones Zhang Nan and Zhao Yunlei.
With the Chinese pair already through, the match lacked intensity and the arena had half-emptied following the disappointment of Ouseph's loss. Bankier let frustration get the better of her in the second game and was shown a yellow card by the umpire for misconduct before Zhang and Zhao won 21-13 21-14.