Great Britain "can't be satisfied by just reaching the semi-finals" as they prepare to face Australia in the last four of the Billie Jean King Cup, says captain Anne Keothavong.

They beat Spain 3-0 on Thursday to reach the semi-finals of the event for the first time since 1981.

"We go into the match as underdogs but we have the home support," Keothavong told BBC Sport.

"We still have a job to do but we have put ourselves in a fantastic position."

Olivia Nicholls, who sealed Britain's last-four place by winning the doubles rubber against Spain alongside Alicia Barnett, said the "sky's the limit" for the hosts.

"I don't see there are any players or teams here that we should walk on to court thinking we can't beat. We will just keep going," said Nicholls.

There will be two singles matches before the doubles in the best-of-three tie, with Harriet Dart, Heather Watson and Katie Boulter also in the GB squad.

Britain have been runners-up in the competition - previously known as the Fed Cup - four times but have never won it.

GB 'creating memories together'

Great Britain go into the semi-final buoyed by the stunning way they got there, defeating the higher-ranked Spain to win Group C, having been on the brink of elimination since losing their opening tie against Kazakhstan.

Britain needed other results to go their way and then to whitewash Spain to stay alive. They did so with an inspired Watson and Dart triumphing in singles before doubles specialists Barnett and Nicholls completed the job at a jubilant Emirates Arena.

Keothavong described it as "the biggest win certainly in my time as captain" after "a fantastic day with incredible performances".

She added: "What took everybody, me included, by surprise was the manner they were able to deliver those victories. To win without dropping a set was quite incredible. It was something special.

"The players are playing with a lot of belief and they have appreciated the support out there."

GB did not even qualify for this year's finals initially, having been beaten by the Czech Republic in a play-off in April, but made the final 12 because they were later named as hosts.

Keothavong, who played in the competition between 2001 and 2013 before becoming Great Britain captain in 2017, was emotional on court on Thursday after Barnett and Nicholls' doubles win.

Referencing Britain's most recent semi-final appearance in 1981, Keothavong said: "Last time it happened was before I was born, not just the players.

"This competition means so much to me for so many different reasons. It's the relationships, the journey and the camaraderie along the way. We've spoken in the debrief about wanting to create memories together and we are doing that."

Opponents Australia, who defeated Belgium and Slovakia to win Group B, have a squad featuring world number 33 Ajla Tomljanovic, Storm Sanders, ranked 237, and 2011 US Open champion Sam Stosur, who now focuses on doubles.

"Australia have a huge amount of experience in the competition," Keothavong said. "Their number two player, Storm Sanders, we cannot underestimate her. You look at her ranking on paper but she rises to the occasion."

Australia won the Fed Cup/Billie Jean King Cup seven times between 1964 and 1974 but have lost nine finals since then.

Tickets are still available for Saturday's matches with the second semi-final, due to start at 16:00, between Switzerland and the United States or the Czech Republic, who meet in a straight shootout to decide the winners of Group D on Friday.

Analysis

BBC tennis correspondent Russell Fuller in Glasgow

Virtually everyone has heard of Billie Jean King, but far fewer know exactly what the Billie Jean King Cup is about.

Great Britain's magnificent 3-0 win over Spain will give the rest of these Finals real impetus, but it is hard to rationalise how Britain have reached a World Cup semi-final by winning only one tie. Especially as they were knocked out by the Czech Republic in April's qualifying round.

Reinstated as hosts, they have seized their opportunity gloriously and topped a group featuring Kazakhstan's Wimbledon champion Elena Rybakina and Spain's Paula Badosa, until very recently an established member of the top 10.

Australia will have the highest-ranked singles player in the semi-final, as Ajla Tomljanovic has been in the quarter-finals of both Wimbledon and the US Open this year.

They also have a wealth of doubles options with Sam Stosur, Storm Sanders and Ellen Perez all in the squad.

But Australia are, on the face of it, less intimidating opponents than either Spain or Kazakhstan, and Britain are playing with house money and increasing home support.