British No 1 Laura Robson was eliminated from Wimbledon after Estonia's Kaia Kanepi beat her 7-6 (8-6) 7-5 on Court One.
Robson was a match for her opponent for the vast majority of the contest but was found wanting in the crucial moments at the end of both sets.
The 19-year-old served for the first set and went 5-2 up in the subsequent tie-break, but ultimately buckled under the pressure and could not find a response in the second.
Kanepi is through to the last eight at Wimbledon for the second time in her career and will now face Sabine Lisicki after she dumped out defending champion Serena Williams.
Robson took to the court with ambitions to become the first British woman in 29 years to reach the Wimbledon quarter-finals, and initially it was Kanepi who seemed to be letting the occasion get the better of her.
Robson took the Estonian to deuce in the opening game before holding to love. A double-fault handed Robson her first chance to break, but Kanepi came up with a strong serve.
Kanepi continued to struggle with double-faults but the serves she did land were proving hard to return and Robson could not break.
Still, Robson looked by far the more comfortable of the two players and finally broke Kanepi in the ninth game, only to let her back in straight away following a loose service game.
A tie-break followed and Robson quickly took control, but she then lost four straight points to hand the initiative to Kanepi, who eventually sealed the set from the baseline.
Robson was on the ropes early in the second set, handing Kanepi a break point in the first game, but she responded with a 99mph ace before going on to hold.
The set continued to progress with serve until the 11th game when Robson, serving to move 6-5 ahead, capitulated completely and was broken to love.
Robson did show some grit by saving four match points in the next game, but could not prevent Kanepi from serving it out.