- Holders Czech Republic beat Germany 4-1 to reach Fed Cup semifinals
- World number two Petra Kvitova won both of her singles matches in Stuttgart
- Serbia and Russia also through and they will face each other in semifinals
World number two Petra Kvitova won both of her singles matches to guide holders Czech Republic into the Fed Cup semifinals with a 4-1 victory over Germany in Stuttgart.
Wimbledon champion Kvitova won her match against Julia Gorges on Saturday -- and her 6-7 6-4 6-1 success over Sabine Lisicki in Sunday's opening singles rubber ensured the Czech had an unassailable 3-0 lead.
Angelique Kerber restored some pride for the hosts with a 6-4 6-4 win over Lucie Hradecka, but Iveta Benesova and Barbara Zahlavovoa Strycova combined to win the final doubles rubber to secure a convincing victory.
"I had trouble with my returns at the beginning, but I knew what I had to do and things improved in the second set," Kvitova -- who was winning her eighth Fed Cup match in a row -- told the official tournament website.
The Czechs will now face Italy in April's semifinals, while Germany face a relegation match to stay in the World Group top tier.
Italy sealed their place in the last four when Flavia Pennetta and Roberta Vinci beat Ukrainian pair Lesia Tsurenko and Olga Savchuk 7-5 0-6 6-1 in the deciding doubles rubber in Biella.
Meanwhile, Svetlana Kuznetsova guided Russia through to the semifinals with a 3-2 victory over Spain in Moscow.
Leading 2-0 from the first day, the hosts suffered a blow when world number three Maria Sharapova pulled out of Sunday's opening singles through illness.
And her replacement Nadia Petrova proved no match for Carla Suarez Navarro, with the Spanish No.1 romping to a 6-0 6-3 win in just over an hour.
It was left to former French and U.S.Open champion Kuznetsova to complete the job for Russia, defeating Silvia Soler-Espinosa 6-2 4-6 6-3 in a hard-fought encounter.
Spain won the dead doubles rubber, but it is Russia who go through to a last four encounter with Serbia.
The Serbs secured their first-ever semifinal place with a thrilling 3-2 win over Belgium in Charleroi.
When Yanina Wickmayer thrashed Aleksandra Krunic 6-1 6-0 to put the hosts 2-1 ahead, things looked bleak for Serbia.
But despite the absence of star player Jelena Jankovic with a thigh injury, the visitors rallied and Bojana Jovanovski leveled the tie with a 6-2 6-4 victory over Kirsten Flipkens.
And the turnaround was complete when Krunic and Jovanovski combined to defeat Wickmayer and 17-year-old debutant Alison van Uytvanck 7-6 4-6 6-1in the deciding doubles.
Meanwhile, in the World Group second tier, Serena Williams completed her second singles win on her Fed Cup return to help the United States beat Belarus 4-1 in Worcester, Massachusetts.
Williams rallied from a set down to beat Anastasia Yakimova 5-7 6-1 6-1, to follow on from her victory over Olga Govortsova on Saturday.
Yakimova was a late replacement for Australian Open champion and new world number one Victoria Azarenka, who was forced to withdraw with a back injury.
The United States, who have won the competition a record 17 times, are playing in the second tier for the first time and must now win a playoff to return to the elite group in 2013.