Andy Murray beat Carlos Moya 2-6, 6-3, 6-1 to complete a spirited fightback and move into the semifinals of the Cincinnati Masters here on Friday. The eighth-seeded Scot will test his confidence against the mighty serve of Ivo Karlovic, who notched 24 aces in his 7-6 (8-6), 7-6 (7-3) quarterfinal win over German Philipp Kohlschreiber. On Thursday, the Croatian giant opened the door for Roger Federer to lose his No. 1 ranking to Rafael Nadal as he stunned the Swiss in the third round. Nadal, who faced Nicolas Lapentti of Ecuador later Friday, can clinch the top spot on Monday by winning the Sunday final. Third seed Novak Djokovic was playing good friend Ernests Gulbis in a quarterfinal. Murray's success took just over 90 minutes as he turned around a desperate situation, down a set and a break in hot summer conditions. The Briton goes in with full confidence after reaching his fifth career semi-finalat the elite Masters level. “I think I can win a Masters Series, and I'd love to do it this week. I played well last week and had a tight match against Nadal. “This week I'm playing well again. You know, hopefully I can do it.” Moya, at 31 a decade older than Murray, ran out of puff after his initial fast start. On Thursday, Nadal shifted into position to seize the No. 1 ranking with a 6-4, 7-6 (7-0) defeat of Tommy Haas. In the wake of his Thursday third-round win over the German, Nadal stands three victories away from taking the ATP top spot from Federer. If he claims the title on Sunday, the deal is sealed. Jankovic toppled Jelena Jankovic was upset 7-5, 6-2 by Slovakia's Dominika Cibulkova in the quarterfinals of the Montreal Cup on Friday, ending her chance of replacing fellow Serb Ana Ivanovic as world number one this week. Following a shock third-round exit on Thursday, Ivanovic had left the door open for world number two Jankovic to nudge her out of top spot by reaching Sunday's final. But for the second consecutive week, Jankovic failed to seize her opportunity, suffering a stunning centre court collapse at the hands of the 19-year-old Slovak. “It doesn't matter, the first ranking. I want to be healthy,” Jankovic told reporters. “I don't really think about number one.” Cibulkova faces Marion Bartoli in Saturday's semifinals after the 10th-seeded Frenchwoman advanced with a 6-2, 6-3 win over Japan's Ai Sugiyama. In the other quarter-finals, world number four Svetlana Kuznetsova faced seventh seed Safina in an all-Russian showdown while 17-year-old Austrian Tamira Paszek, who upset Ivanovic, was due to play 11th seed Victoria Azarenka of Belarus. On Thursday, Ivanovic was knocked out by Tamira Paszek 6-2, 1-6, 6-2. Jankovic advanced to the quarterfinals with a 6-3, 6-2 win over Stephanie Dubois and Cibulkova upset 12th-seeded Nadia Petrova 7-6 (2), 6-2. Bartoli also advanced after overcoming Russian sixth seed Anna Chakvetadze 4-6, 7-5, 7-6. Zvonareva for Sharapova Vera Zvonareva will replace the injured Maria Sharapova at the Beijing Olympics, Russian tennis federation official Vladimir Kamelzon said on Friday. Kamelzon said that Fed Cup skipper Shamil Tarpishchev had been in charge of naming Sharapova's replacement after the world number three withdrew earlier Friday with a shoulder injury.