Storm Sanders and Ajla Tomljanović have swept Australia into the semifinals of the Billie Jean King Cup in Glasgow, full of belief they can now end their country's 48-year wait to lift the World Cup of women's tennis.

The pair — who both won their singles matches in Tuesday's victory over Slovakia — again produced the goods to seal a 3-0 whitewash of Belgium in Thursday's winner-takes-all group decider.

Sanders beat Alison van Uytvanck 6-2, 6-2, before Elise Mertens retired with a shoulder injury when trailing 3-0 in the deciding third set against Tomljanović.

The inspired Sanders also won her doubles rubber alongside the evergreen Sam Stosur as Alicia Molik's team reached the last four for the second year running.

Yet they reckon this week's run in Scotland feels different to Prague last year, when they bowed out with a loss to Switzerland.

"We are in a better position coming into the semis this time; more confident, where we believe like we can actually win," Australian number one Tomljanović said.

"Last year we were, like: 'Wow, we made the semis, what a great achievement.' This year it feels a little bit different, as it should. We have showed really great tennis to get ourselves there. [It] feels good to be in that position."

Sanders — who is ranked 237th in the world — appeared once again to be buoyed by the singles responsibility for her country as she blew away world number 54 van Uytvanck to put Australia one-up.

Then Australia's top player stayed tough to extinguish Belgium's last hope, wearing down Mertens, who had begun in blistering fashion by taking the opening stanza 6-4 and going 4-1 up with a double break in the second.