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Great Britain 1-2 Australia - best-of-three tie
Singles 1: Heather Watson 4-6 6-7 (3-7) Storm Sanders
Singles 2: Harriet Dart 7-6 (7-3) 6-2 Ajla Tomljanovic
Doubles: Alicia Barnett/Olivia Nicholls 6-7 (1-7) 7-6 (7-5) 6-10 Storm Sanders/Sam Stosur
GB's first semi-final in competition since 1981
Second semi-final: Switzerland v Czech Republic (after GB v Aus)
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Dart 3-0 Tomljanovic*
This is sublime stuff from Harriet Dart, she's taken full control of this opening set.
A love hold is sealed as Ajla Tomljanovic finds the net. Eight minutes played and Dart is three games to the good in a must-win match.
*Dart 2-0 Tomljanovic
More positive play from Harret Dart and she finds herself with two break points.
She gets the break at the first time of asking, finished with a flourish at the net.
A superb start for GB.
Image source, Getty ImagesDart 1-0 Tomljanovic*
Not the start Harriet Dart would have wanted as she slipped to 0-30 on serve, but she battles back into the opening game and turns it around, getting the important hold early on.
*Dart 0-0 Tomljanovic (*denotes next server)
Ajla Tomljanovic won the toss and elected to receive, so Harriet Dart gets us under way.
She has to win this tie, or Great Britain are out of the Billie Jean King Cup.
Dart has lost to Tomljanovic on the two previous occasions they have met.
All eyes on Harriet Dart now.
She faces world number 33 Ajla Tomljanovic in the second singles rubber to try and salvage this semi-final for Great Britain.
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Watson 4-6 6-7 (3-7) Sanders
Heather Watson has been speaking to the press after her defeat by Storm Sanders.
“I really enjoyed being out there on court today again. I don't feel like I played as well as I did in the first match [against Spain], I felt a bit heavier today, missed a lot more first serves.
"I think I just didn't feel as fresh as I did then. It's very different playing at 10am when we have been having late starts.”
Watson 4-6 6-7 (3-7) Sanders
Russell Fuller
Tennis correspondent at Emirates Arena
A deserved win for Storm Sanders - her approach to the match epitomised by the tie-break in which she hit five winners.
She really went for her shots, while Heather Watson was rather pushing the ball back at her at the climax and seemed a little inhibited throughout.
Watson 4-6 6-7 (3-7) Sanders
"Gosh, I can't really talk right now, I'm shaking," Storm Sanders said in her on-court interview.
"That was amazing, Heather is a really, really good player and playing in front of a home crowd means it was going to be a tough ask for us.
"It was a really good match, it could have gone either way, and obviously early on in that second [set] Heather got on a bit of a roll.
"I just tried to stick with her and try to fight, I was able to turn it around and I'm super happy with my performance today."
Mel South
Former British player on BBC TV
You can see the emotion, the relief, it has brought to Storm Sanders. She has got her team to the perfect start. It was almost a perfect tie-break, the lead giving her the freedom.
For Watson it is a heartbreaker, but she fought for everything out there.
Watson 4-6 6-7 (3-7) Sanders
There it is. First blood to Australia as Storm Sanders beats Heather Watson in straight sets.
Watson nets to hand the rubber to her opponent. A brilliant effort from the Brit though.
Watson 4-6 6-6 (3-6) Sanders*
First match point saved as a very energetic Sanders goes long. She then finds the net, but she still has three match points remaining.
Mel South
Former British player on BBC TV
This has been a phenomenal tie-break from Storm Sanders.
*Watson 4-6 6-6 (1-6) Sanders
Watson finds the net to extend Sanders' lead in the tie-break and it's an uphill battle from here.
A cross-court forehand from the Australian earns her five match points.
Watson 4-6 6-6 (1-4) Sanders*
A tussle at the net ends in a huge roar from Heather Watson as she gets a point on the tie-break board, but Sanders replies with a forehand into empty space.
*Watson 4-6 6-6 (0-3) Sanders
Advantage Australia, as Storm Sanders wins the first three points of the tie-break.
*Watson 4-6 6-6 Sanders
A love hold for Storm Sanders - the first of the match - and we're headed to a tie-break.
A big, big moment for Heather Watson here.
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Russell Fuller
Tennis correspondent at Emirates Arena
Heather Watson has not been able to play with the same freedom and fluidity of Thursday evening, but she is hanging in there in the biggest match she has ever played for her country.
Watson 4-6 6-5 Sanders*
Wasp dealt with, Watson delivers an ace - her third today - to get the game started.
A brilliantly served game results in a hold to 15 and Watson again puts the pressure on Sanders to stay in the set.
Gigi Salmon
BBC Sport tennis commentator
Don't make it angry! The wasp is following Watson around. A brave ballboy tried to catch the wasp in his hand. I do not advise that.