Fifth seed Elena Dementieva recovered from a mid-match meltdown to beat fellow Russian Nadia Petrova 6-1, 6-7, 6-3 on Tuesday and reach her first Wimbledon semi-final.
Dementieva was a set and 5-1 up after a one-sided encounter that Petrova barely seemed to be taking part in other than to produce a steady stream of forehand errors.
With the finishing post within touching distance and serving for the match, Dementieva threw the 21st seed an undeserved lifeline by double-faulting to hand Petrova her first break.
Another break by Petrova followed and what should have been an easy win suddenly turned into a more intriguing encounter.
Dementieva, the highest remaining women's seed in the draw, held two match points in the second-set tiebreak but could not convert them, enabling Petrova to force a decider.
It was a situation all too familiar for Dementieva, who was knocked out of the French Open quarter-finals by Dinara Safina after squandering a match point in the second set. She said she could not stop thinking about how things had slipped away from her that day.
"I was so close to finishing in two sets and I don't know what happened," she said. "I suddenly started to think about the French Open quarter-finals and it was difficult (to get that out of my head). It was so exhausting."
Petrova, wearing strapping on her right knee, said her concentration had been thrown in the fourth game of the first set when she was called for a foot fault for marginally stepping the wrong side of the centre line.
"After losing that, I gave her a lead of 4-1, so it was difficult to catch up already in the second set," Petrova told a news conference.
She added that her performance had also been affected by the late finish of her mixed doubles match the previous evening.
"I also felt a little bit tired from last night because I finished playing mixed at 9pm. It was not enough time to recover." Petrova seemed unable to build on what should have been a big confidence boost after clawing her way back into the match and instead started producing the type of unforced errors that had riddled her play in the first dozen games.
The 26-year-old Dementieva stormed to a 4-0 lead in the third set and finally wrapped up the match with a scorching forehand crosscourt winner to set up a last-four encounter with champion Venus Williams, a 6-4, 6-3 winner over Thailand's Tamarine Tanasugarn.
"She's the defending champion, it's all pressure on her," Dementieva said, looking ahead to her next match. "I really have nothing to lose, you know."
Zheng to face Serena next
The remarkable Zheng Jie beat 18th seeded teenager Nicole Vaidisova 6-2, 5-7, 6-1 on Tuesday to reach the semi-finals where she will meet former champion Serena Williams, an easy 6-4, 6-0 winner over Poland's Agnieszka Radwanska.
Zheng, who upset top seed Ana Ivanovic in the third round, broke Vaidisova twice in the opening set, both times when the Czech 19-year-old double faulted on break point. Zheng, in turn, saved six break points in the set.
The Chinese, a former world number 27 who came into the tournament ranked 133 after injuries, is the first women's wildcard to reach the semi-finals.
She dropped a set for the first time here when Vaidisova broke her for the second time in the 11th game of the second set and went on to level the match.
It is a first grand slam semi-final for Zheng, whose previous best at was reaching the third round in 2004 and whose best grand slam was the fourth round at the French Open in 2006 before an ankle injury put her out for most of 2007.
The feisty Zheng, whose two-handed backhand hit low over the net is a formidable weapon, was too much to handle for Vaidisova, who had beaten her in their two previous meetings.
The Chinese, who turns 25 on women's final day on Saturday, set up two break points in the second game of the first set and the Czech double faulted on the second.
The same happened in the eighth game when Vaidisova again served a double fault to relinquish the set.
Vaidisova, whose best showings at a grand slam are the semi-finals at the 2007 Australian Open and 2006 French Open, gained consistency in the second set while Zheng tired.
However, Zheng proved the more resilient, racing away with the third set, although she needed a third match point to settle it when the Czech sent a return into the net.