MOSCOW (AFP) - World number one Jelena Jankovic of Serbia battled through the pain barrier on Thursday to beat Russian Vera Dushevina and advance to the quarter-final of the Kremlin Cup, a 2.4-million-dollar joint ATP and WTA event. But there was no such trauma for the ATP event's top seed, Nikolay Davydenko of Russia barely breaking sweat as he dispatched Spaniard Guillermo Garcia-Lopez 6-1, 6-1. Jankovic, 23, dropped the first set and was 2-0 down in the second before receiving on-court treatment and gaining her composure to win 6-7 (6/8), 6-3, 6-2, her fourth win over Dushevina in their five head-to-head meetings. "Today I felt pain in my back when I practised and during the match I was feeling more and more pain," Jankovic said. "It was really difficult to play as I was struggling the pain. "I felt worse and worse and was even ready to quit playing when I was one set and 2-0 down. "But after the doctor put that anesthetic cream on my back and I took the pain killer everything changed. I did my best trying to serve well and it worked." The rivals traded breaks throughout the opening set before the 22-year-old Russian wildcard won 8-6. In the second Dushevina, currently ranked 77th in the world, broke immediately for a 2-0 lead but Jankovic broke back twice to level at one set all. Jankovic started the third set with a couple of breaks for a commanding 4-0 advantage and proceeded to wrap up the game and set up her 19th quarter-final in the 20 tournaments she has played this season. Russia's Vera Zvonareva, who was seeded seventh here, also booked a quarter-final pass, outclassing Slovakia's Daniela Hantuchova 6-1, 6-0 to record her fourth head-to-head win in as many meetings. Zvonareva, currently ninth in the world, ran out to a 4-0 lead before Hantuchova even chalked up her first point of the match. After winning the opening set in 23 minutes, the 24-year-old Russian underlined her supremacy in the second, taking it at love to set up a meeting with another Slovak, Dominika Cibulkova, for a place in the semis. "I didn't make any unforced mistakes," Zvonareva said. "I was serving and returning well. But I know that one can have just one or two such easy matches during the season." On the ATP event, Davydenko was pleased with the 56-minute masterclass he handed Garcia-Lopez. "The score speaks for itself. I played confidently and controlled the match," said the local favourite who is seeking his fourth title in home events this year. In the semi-finals, Davydenko will meet seventh-seeded compatriot Marat Safin, who beat Frenchman Julien Benneteau 6-4, 0-6, 6-2.Another Frenchman Paul-Henri Mathieu, the 2002 champion here, battled into the quarter-finals from a set down, beating Dudi Sela of Israel 6-7 (3/7), 7-5, 7-6 (7/0) to face compatriot Fabrice Santoro. Meanwhile, Serbia's Viktor Troicki upset his eighth-seeded compatriot Janko Tipsarevic, ousting him in straight sets 6-3, 6-4 to set up a match against Germany's Mischa Zverev, a 6-2, 2-6, 6-1 winner over Russian Teimuraz Gabashvili.