A pair of dramatic, deciding doubles rubbers were the statement victories on a Sunday in which eight nations became four in the Fed Cup, as France, Germany, the Czech Republic and the United States advanced to April's Fed Cup semifinals. 

World Group Quarterfinals

Czech Republic 3 - 1 Switzerland
France 3 - 2 Belgium
Germany 3 - 2 Belarus
USA 3 - 1 Netherlands

Both France and Germany advanced to the next round by virtue of three-set wins in the fifth rubber, after seeing Saturday's play conclude with their ties even at 1-1, and singles action also being split on Sunday.

Read more: Mladenovic leaves France level after Day 1

With action in Mouilleron le Captif even at 1-1 after wins by Kristina Mladenovic and Elise Mertens on Saturday, it was the French No.2 who earned victory over the Australian Open semifinalist in straight sets, 6-4, 6-4 in the first reverse singles match of the day.

Nonetheless, a change in nomination paid off in a big way for Belgian captain Dominique Monami.

She called upon Alison van Uytvanck to replace Kirsten Flipkens in the second singles match, and the former French Open quarterfinalist defeated Pauline Parmentier with the loss of just four games, setting up a decisive doubles rubber between Mladenovic, Mertens, Flipkens and Amandine Hesse.

Early advantages in both sets ensured a decider would be played, but in front of a raucous home crowd, Mladenovic and Hesse won the first four games of the final set to the tune of a 6-4, 2-6, 6-2 victory. 

For Hesse, appearing in her first live rubber, the joy in reaching the Fed Cup semifinals proved unbridled. 

“I couldn’t wait to win this match, I was so excited,” she told reporters and fedcup.com after the match. “My stomach was so painful. I was trying to stay focused and Kiki helped me a lot with this. She was telling me every point, ‘Relax, we will do it, take your time.' I think it helped me a lot today.”

While France shined at home, the Germans defied the odds on the road with a stunning upset of top seeds and last year's finalists, Belarus, in Minsk.

Tatjana Maria and Anna-Lena Groenefeld came from a set and a break down, as Belarus served for the match, to defeat Aryna Sabalenka and Lidziya Marozava, 6-7(4), 7-5, 6-4 in the decisive doubles to put the two-time Fed Cup champions into the semifinals for the first time in three years. 

“It’s amazing what we’ve achieved today. The whole team has been fighting all week long,” Maria told reporters and fedcup.com after the match. “I think we won this tie because everyone in the team has been positive the whole time. We are so together, without them we wouldn’t be here.”

With Top 10 players Angelique Kerber and Julia Goerges, German No.3 Carina Witthoeft or stalwart Andrea Petkovic, Maria proved to be Germany's top-ranked player in the tie, and the World No.57 also earned a three-set singles victory over Vera Lapko in the first singles match of Sunday's play.

However, Sabalenka came from a set down to defeat Antonia Lottner - who, making her debut this week, had scored a win over Aliaksandra Sasnovich on Saturday - to send the tie the distance. 

“It was a pretty incredible match. We tried our best,” said Sabalenka. “They showed a great level and we also brought a good level. They won some crucial points in important moments. I really enjoyed playing it.”

Behind Petra Kvitova and Venus Williams, the Czechs and Americans enjoyed smooth sailing through to the semifinals at home.

Kvitova earned a victory over Belinda Bencic to put the Czechs through to the semifinals for a staggering 10th straight year, while Williams' straight sets victory over Richel Hogenkamp ensured the defending champions a return trip to April's final four.

Read more: Serena makes competitive return in Fed Cup doubles

However, Switzerland and the Netherlands would not go home empty-handed, as Timea Bacsinszky and Jil Teichmann and Demi Schuurs and Lesley Kerkhove were nonetheless victorious in the doubles rubbers to deny the home teams a clean sweep.

In Asheville, former World No.1 Serena Williams made her official return to competitive tennis alongside sister Venus in doubles. 

The four losing nations will be drawn against the four victorious nations from World Group II - Italy, Australia, Romania and Slovakia - for the right to play in the 2019 World Group.