Czech Republic up 2-0 on Serbia
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The eighth-ranked Kvitova, who led the Czechs to victory over Russia last year in the final, pumped her fist after securing her 11th consecutive victory in Fed Cup singles. She showed no signs of the bronchitis that forced her to withdraw from the WTA Championships last week.
"Unbelievable," said Kvitova, who hit 28 winners compared to 15 by Jankovic. "Actually, I was surprised by how I played. I didn't know what I can expect from myself on the court."
Kvitova could clinch the title on Sunday in the first reverse against Ivanovic. The Serb leads their matchups 3-1, but Kvitova won their last meeting in the Australian Open.
It was the first Fed Cup loss in two years for Jankovic.
Kvitova double-faulted to drop serve in the fifth game before breaking twice to take the first set. Applying her big forehand and serve, she took a 5-0 lead in the second. She converted her second match point when Jankovic's backhand sailed long.
"She was really on a roll," Jankovic said. "I had chances in the first set, but she came up with really some unbelievable shots. There was nothing I could do at times. She had a great day."
Ivanovic was unable to find her rhythm throughout their match, hitting eight double-faults and making 32 unforced errors.
"I'm very, very disappointed that I didn't manage to get the first point for our team," she said. "I had plenty of opportunities, but I just wasn't executing when it was important. It was very frustrating."
The Czechs won their first title last year since Czechoslovakia's split in 1993. Czechoslovakia won five times, including three straight from 1983-85.
Copyright 2012 by The Associated Press