By Simon Evans
MASON, Ohio (Reuters) - Top-seed Jelena Jankovic of Serbia and second seed Caroline Wozniacki suffered surprise third-round exits in the Cincinnati Open on Thursday.
In fierce heat, champion Jankovic fell 7-6 6-4 to Uzbek qualifier Akgul Amanmuradova, who now meets another Serb, Ana Ivanovic, in the quarter-finals.
Polish seventh seed Agnieszka Radwanska also lost 6-2 6-3 to 10th seeded Russian Maria Sharapova, leaving just two of the top 10 seeds in the tournament.
The biggest upset though was the departure of former world number one Jankovic.
The 25-year-old lost in similar fashion in San Diego last week, exiting in the second round to Russian Alisa Kleybanova, which she blamed on an ankle injury from July.
On Thursday though, the Serbian said technical and tactical issues, not physical problems, were behind her loss.
"I'm healthy now. It's just a matter of getting matches and playing, being in this kind of situations, you know, challenging myself," Jankovic told reporters.
"Hopefully I will do better in my next tournament (next week in Montreal). That will be my last preparation tournament before the U.S. Open."
Wozniacki was up 4-3 in the first set but then Bartoli rallied to claim the opening set and dominated the second where she won 14 of 16 first-serve points.
Bartoli will meet Sharapova in the quarter-finals.
Wozniacki flew to Ohio after winning last week's Danish Open and said she may have paid the price for the demanding schedule.
"Definitely it was a factor, there is no doubt about that, getting here late and then getting used to the weather and playing outdoors," she told reporters.
"But it was my choice to play there and then come here."
Eighth-seed Li Na of China also suffered an early exit, losing to Belgian Yanina Wickmayer 2-6 6-2 7-6 in an exciting three-set encounter.
The only other top 10 seed, apart from Sharapova, to have survived the cull is fourth seeded Belgian Kim Clijsters, who will face Pennetta on Friday having crushed 18-year-old American Christina McHale 6-1 6-1.
(Editing by Frank Pingue/Greg Stutchbury)