Russia came from 2-0 down to beat France on Sunday and book a Fed Cup semifinal against two-time defending champion Italy.
Italy won all three of Sunday's matches to beat Australia 4-1, while Belgium's comfortable 4-1 win over the United States set up a semifinal against the Czech Republic, which saw off Slovakia 3-2.
Russia lost both singles matches on Saturday, but captain Shamil Tarpischev's decision to replace three-time Grand Slam champion Maria Sharapova with Anastasia Pavlyuchenkova on Sunday proved inspired.
Pavlyuchenkova beat Alize Cornet 3-6, 6-3, 6-2 in the first reverse singles and later teamed up with Svetlana Kuznetsova to win the doubles and complete Russia's comeback in Moscow.
Russia was only the fourth team since 1995 to come back from 2-0 down to win a Fed Cup World Group tie.
The 14th-ranked Pavlyuchenkova lost to Francesca Schiavone of Italy on her debut in the 2009 semifinals, but recovered from losing the first set to see off Cornet on Sunday.
''The pressure on me was really tough,'' she said. ''On the court today, I often remembered that my first match was also a decisive one. I thought that if I lose this one as well I would not survive it.''
Kuznetsova, who lost in three sets to Cornet on Saturday, leveled the tie at 2-2 with a 6-4, 6-4 win over Virginie Razzano before Pavlyuchenkova and Kuznetsova won the doubles 7-6 (4), 6-0 to send Russia into the semifinals and extend its unbeaten home run to eight ties.
Russia's reward is another home tie against Italy, which extended its Fed Cup winning streak to seven ties by beating Australia.
Schiavone put Saturday's surprise loss to Jarmila Groth behind her with a gruelling 7-6 (1), 3-6, 7-5 win over Sam Stosur in a repeat of last year's French Open final, also won by the Italian player.
Flavia Pennetta sealed Italy's progress by winning her 10th straight Fed Cup match, 6-3, 6-2 over Jarmila Groth.
''We have to be really happy about this match,'' Penetta said.
Roberta Vinci and Sara Errani of Italy beat Anastasia Rodionova and Rennae Stubbs 2-6, 7-6 (1), 6-4 in the doubles in Stubbs' last before retiring after a 25-year pro career.
Belgium made light of the absence of the recently retired Justine Henin with a dominant 4-1 win over the United States, which was without the Williams sisters.
The hosts were already 2-0 up after the first day and the No. 2-ranked Kim Clijsters beat Bethanie Mattek-Sands 6-7 (10), 6-2, 6-1 in Sunday's opening match to seal the win.
''It really feels good to see that 3-0 on the board so soon,'' Clijsters said.
Yanina Wickmayer gave Belgium a clean sweep in the singles with a 6-2, 6-0 win over Melanie Oudin, before Liezel Huber and Vania King scored a consolation point in the doubles by beating Kirsten Flipkens and An-Sophie Mestach 6-3, 7-5.
''Unfortunately we came up against a better team in Belgium,'' U.S. captain Mary Joe Fernandez said. ''It was really too tough with Kim Clijsters and Yanina Wickmayer, they really were a level above.''
Up next for Belgium is a home tie against the Czech Republic, which sealed its progress when Petra Kvitova won her second singles match of the tie by beating Slovakia's Daniela Hantuchova 6-4, 6-2.
''It was one of my best performances in the Fed Cup,'' Kvitova said. ''We came here in great shape while (Hantuchova) is still not in her best form.''
Kvitova's win put the Czechs 3-0 up before Slovakia won the final two meaningless matches.
Slovakia, like all the teams beaten in the first round, will go through to the World Group playoffs on April 16-17, when the semifinals will also be played.
