Top-seeded Russian Maria Sharapova led the way into the women's semi-finals at the US Open on Tuesday, with a 7-5, 4-6, 6-4 victory over ninth-seeded compatriot Nadia Petrova.
"I don't know what I'm doing here," said a relieved Sharapova, who started strong and raced to a 4-0 lead behind a sparkling forehand before errors stalled her charge against the determined Petrova.
The ninth seed battled back, winning the next four games to level the set.
That run included not only two breaks of the Sharapova serve but also a hard-fought hold of serve in which Petrova served a double fault but still denied Sharapova two break chances.
"I thought it was too easy in the beginning," Sharapova said. "I was making winner after winner. And then all of a sudden I went out of the stadium."
Sharapova got the needed break in the 12th game, but she didn't have long to savour it.
Petrova, who had taken Sharapova to a first-set tiebreaker before falling to her in the Wimbledon quarter-finals, opened the second set with a quick service break.
She couldn't widen the gap, but she made it stand up as errors kept both players from developing any momentum.
"We both were on and off," Petrova said. "We both had some great points and we both had some bad - a lot of unforced errors. But we both fought hard and stuck to the end."
{{/usCountry}}"We both were on and off," Petrova said. "We both had some great points and we both had some bad - a lot of unforced errors. But we both fought hard and stuck to the end."
{{/usCountry}}Sharapova cleaned up her game in the third set and took a 3-0 lead with one service break.
Serving for the match at 5-3 she surrendered the break but she got it back in the next to close it out, nailing a stinging service return that caught Petrova by surprise on the final point.
"Maybe I wasn't expecting it," Petrova admitted. "It went like a bullet."
"So many ups and downs," Sharapova said. "I was serving out for the match, she came out with amazing shots. There was not too much I could do."
In the semi-finals, Sharapova will meet either Belgian Kim Clijsters or American Venus Williams, who closed out Tuesday night's action on the Arthur Ashe Stadium Court.
Clijsters is playing in her first US Open since 2003 after a season plagued by injury that saw her ranking plummet.
The Belian, a former world No 1 who is still in search of a first career Grand Slam, has surged back in 2005, regaining the form she displayed when she was runner-up in the US Open two years ago as she bids to fill a gap on her resume with her first Grand Slam title.
Williams, the 10th seed, reaffirmed her Grand Slam credentials with a triumph at Wimbledon, a fifth major title and her first since the 2001 US Open.
She defeated her sister, Australian Open champion Serena, in the fourth-round to set up the Clijsters clash.
Williams went into the meeting with Clijsters with a 6-3 record over the Belgian. They have split two matches this year, with Clijsters winning their most recent encounter in the final at Stanford, California, just weeks ago.
The two remaining quarter-finals were slated for Wednesday, when third-seeded Amelie Mauresmo met No 12 Mary Pierce in an all-French affair and Russian sixth-seed Elena Dementieva took on world No 1 and second seed Lindsay Davenport of the United States.