Australia fight back after every GB point and earn game point as Alicia Barnett pushes a return well out on her own side of the court.

But GB bring up deuce as Sam Stosur can only deflect a strike out of bounds, only for Australia to win the next point for the hold.

Barnett to serve to keep GB in this opening set.

Mel South
Former British player on BBC TV

The fact Nicholls and Barnett have both come out of university tennis, where they're playing for a team and playing for others, helps them in this scenario.

You get a similar type of energy.

Gigi Salmon
BBC Sport tennis commentator

Once again Alicia Barnett asks for more noise from the crowd and she gets it.

A solid hold to love on Olivia Nicholls' serve and they are still very much in this set despite the break.

The Emirates Arena is a cauldron of noise - can that help GB?

Image source, Getty Images

Australia look to be set for the love hold but at 40-0 up, Sam Stosur smashes an overhead volley into the net from close range. She laughs it off - easy to do when you're a break up.

They hold to 30. Olivia Nicholls to serve next for GB.

Russell Fuller
Tennis correspondent at Emirates Arena

A reminder of just what Barnett and Nicholls are up against.

Storm Sanders is a top ten doubles player, who has won three titles this year. And Sam Stosur, in addition to her US Open singles title, has won seven other Grand Slam doubles titles and been a world number one.

One disadvantage might be that I don’t think they had ever played together before Thursday.

With Alicia Barnett on serve, GB canter to a 40-0 lead but can't secure the love hold.

Australia fight back to 40-30, Storm Sanders whipping a forehand cross-court to give her country hope in this game, and it does the job as they then level at deuce.

But a peach of a forehand down the line from Alicia Barnett wins the point and the hold for GB.

Alicia Barnett and Olivia Nicholls go 0-30 up on Australia's serve but Aussies quickly bounce back to lead 40-30, and secure the hold as GB net from close range.

Australia find themselves with a break point after successfully challenging a call of out on a baseline shot.

The Brits navigate the danger however and it is saved, taking us to deuce. But with no ad-scoring, Australia get the break with a ripper of a forehand on the next point.

An ace down the middle from Samantha Stosur brings two game points for Australia.

GB save the first with nippy play at the net, but Australia hold to 30 with a volley at the net from Storm Sanders.

A solid start for Great Britain.

The points go back and forth across the net before Olivia Nicholls earns GB game point at the net. They clinch the hold as Samantha Stosur fails to clear the height.

It's already clear to see how much Nicholls and Barnett are relishing this experience.

GB to serve first.

A slightly different format for doubles.

The match will be played with no-ad scoring - where the next point wins when a game gets to deuce - and the third set is played as a match tie-break (where the first to 10 points wins).

A reminder of the last time Olivia Nicholls and Alicia Barnett stepped on court in the Billie Jean King Cup...

So Harriet Dart's win means the semi-final is level at 1-1 and we're going to a doubles decider.

Great Britain's fate in the Billie Jean King Cup is in the hands of Olivia Nicholls and Alicia Barnett, with a place in the final at stake.

They will take on Storm Sanders and Samantha Stosur shortly.

Let's hear what Harriet Dart has to say after that incredible win.

"Wow, the support out here has just been incredible," she said.

"I always knew going into this match it was going to be really tough, she's a great player.

"I lost to her before the US Open so I always knew it was going to be a really tough match so I'm pleased to get through and perform really well.

"There's honestly nothing better than walking out here with Great Britain on the back of my shoulders, and every time I walk on to this court I get goosebumps.

"When they say game Great Britain it's so much more than just me and to everyone here, everyone in my team and all the support staff, we're just so excited to be here."

Image source, Getty Images

Harriet Dart is just too good for Ajla Tomljanovic today, she's putting her absolute everything behind each and every stroke.

She races to 40-0 and has three match points...