French Open champion Ana Ivanovic slumped to another dispiriting defeat today when she was knocked out of the Kremlin Cup by unseeded Slovakian Dominika Cibulkova.
Serbian golden girl Ivanovic, who rose to the world No.1 spot after her triumph at Roland Garros in June, has seen her career plunge into freefall and she arrived here having won just five matches in five events since her grand slam breakthrough.
The fourth seed fared no better against the 19-year-old Cibulkova, losing 6-3 2-6 7-6 (7/4).
Ivanovic, 20, now fifth in the world, broke three times in the first set to claim the opener in 36 minutes.
But her opponent broke twice in the second to level at one set all after one hour 19 minutes on court.
The opponents traded breaks twice in the deciding set forcing a tiebreak, which Cibulkova, 20th in the WTA rankings, won to record victory in the pair's first ever meeting.
"I had a bad first set as I was playing too defensively," Cibulkova said. "Later I got more aggressive, I began to serve better and return better.
"I knew I had to play more aggressively in the tiebreak and I did it. I'm happy to beat a player of such a rank."
Russia's Dinara Safina, the second seed at the $US2.4 million ($A3.39 million) joint ATP and WTA event, went through to the quarter-finals seeing off Amelie Mauresmo of France.
The 22-year-old Safina won 6-7 (2/7) 6-4 6-4 in two hours 24 minutes to record her second win over Mauresmo in their seven head-to-head meetings.
In a clash for a place in the semis, Safina will face fifth seed compatriot Svetlana Kuznetsova, who made the quarter-finals ousting Italian qualifier Sara Errani 7-6 (7/0) 6-1 in one hour 21 minutes.
Meanwhile, defending champion Elena Dementieva of Russia, the third seeded Olympic champion, also advanced into the quarter-finals seeing off Slovenia's Katarina Srebotnik winning 6-3 4-6 7-6 (7/2).
Dementieva will now face either compatriot Nadia Petrova or Caroline Wozniacki of Denmark who beat Russians Anna Lapushenkova and Anna Chakvetadze, the 2006 champion here, respectively.
"It took time to adjust to the carpet here and it wasn't easy to win," Dementieva said.
In the men's event, Jeremy Chardy of France battled from a set down to upset second seed, and the 2005 champion, Igor Andreev of Russia 3-6 7-5 6-4 in one hour 52 minutes to reach the quarter-finals.
Another Frenchmen Fabrice Santoro also booked a quarter-final place with a confident 6-2 6-4 win over Uzbeki qualifier Denis Istomin.
Russia's Teimuraz Gabashvili upset third seeded compatriot Mikhail Youzhny 7-5 4-6 7-6 (7/1) to level his head-to head record with this year's Chennai winner Youzhny at 1-1.
Fourth seed Frenchman Paul-Henri Mathieu, the 2002 champion, advanced into the second round beating Sergei Stakhovsky of Ukraine 6-3 6-2.
