Australia and Switzerland completed the semifinal lineup at the Billie Jean King Cup Finals on Thursday, joining Russia and the United States in the final four of the preeminent national team competition in women's tennis.

In the day session, Australia became the third semifinalist in Prague after defeating Belarus 2-1 in a decisive last tie to top Group B.

As in their 2-1 victory over Belgium two days previously, Australia delivered two standout singles wins to capture the tie before the third doubles rubber came into play. Storm Sanders, whose upset of Elise Mertens had been instrumental against Belgium, dismissed Billie Jean King Cup debutante Yuliya Hatouka 6-3, 6-3. She was followed by Ajla Tomljanovic, who had been sidelined due to illness against Belgium but bounced back to defeat Aliaksandra Sasnovich 4-6, 6-2, 6-3.

World No.131 Sanders did not face a break point during her 63-minute win over 21-year-old Hatouka, who had also made her WTA main draw debut this season after qualifying for Strasbourg in May. Tomljanovic needed one hour and 58 minutes to come through a first encounter with Sasnovich, but held her nerve in a final set that saw seven breaks of serve.

Belarus managed to avoid the whitewash by winning the dead doubles rubber, with Sasnovich and Lidziya Marozava defeating Olivia Gadecki and Ellen Perez 6-4, 6-4.

Australia will play Switzerland in Friday's semifinals. The Swiss emerged as the winners of Group D on Thursday night by knocking out hosts Czech Republic 2-1 in the last tie of the round-robin stages.

The Czech Republic has dominated Billie Jean King Cup of late, winning the title six times in the last ten years. But on home soil, the Czechs could not hold on to their favored status as Olympic gold medalist Belinda Bencic of Switzerland won her singles and doubles matches to clinch victory.

The evening session started off well for the Czechs as Marketa Vondrousova defeated Viktorija Golubic 6-4, 6-2. Vondrousova, who won the Olympic silver medal in women's singles this year, took 85 minutes to stop Golubic, who paired with Bencic to win this year's Olympic silver medal in women's doubles.

After that, though, Bencic took control of the tie. First, former World No.4 Bencic engineered a 2-hour upset of current World No.3 and reigning Roland Garros champion Barbora Krejcikova, 7-6(2), 6-4.

Bencic had already knocked out Krejcikova en route to the gold medal in Tokyo, and she repeated the feat over the Czech No.1 in Prague. Bencic saw a 5-2 first-set lead slip from her grasp, but she rallied to take the opening tiebreak and the second set, leveling the tie.

Bencic returned to the court for the decisive doubles clash, partnering with Jil Teichmann. There, the Swiss duo completed the victory, shocking WTA Doubles World No.2 Katerina Siniakova and veteran doubles star Lucie Hradecka, 6-3, 6-3, in just 66 minutes.

The Swiss pair got 70 percent of their first serves into play, and won 88 percent of those points. With that combination, Switzerland was impossible to break -- they faced only a single break point, which they fended off.

Switzerland is aiming for their first Billie Jean King Cup title. Their best result was a runner-up finish to five-time champions Spain in 1998.