Barty won both her singles matches before pairing with Samantha Stosur to claim the decisive fifth doubles rubber 7-5 3-6 6-2 against Aryna Sabalenka and Victoria Azarenka on Sunday.

It took the world No.9's Fed Cup winning streak to 14 and offered Stosur, who had moments of brilliance in the doubles victory, some joy on Pat Rafter Arena after she had lost both singles matches in the tie.

They'll play the winner of the France-Romania tie which is currently locked at 1-1.

Earlier Stosur, who was preferred ahead of the higher-ranked Daria Gavrilova, was blown away when given a chance to seal the tie in a 6-1 6-1 singles loss to former world No.1 Azarenka.

That followed another clinic from Barty, who swept aside world No.10 Sabalenka 6-2 6-2 in another commanding performance less than an hour down the road from her Ipswich home.

Australia's last Fed Cup finals appearance was in 1993, while Evonne Goolagong Cawley played the role of spearhead when they last tasted victory 45 years ago.

An Australian Fed Cup record crowd of 9554 across both days sat mesmerised as both teams threw everything at each other in the tie.

Barty was ice cool all weekend though, striding calmly onto court with three-year-old niece Lucy in her arms on Sunday before switching into game mode.

Australian captain Alicia Molik's decision to stick with Stosur for both of Sunday's matches was a brave one, but the 35-year-old recovered remarkably.

Blown away by Azarenka earlier in the day - Stosur only held serve once all match - the veteran reset to improve her perfect Fed Cup doubles record to 8-0 thanks to some quick hands and assured court craft under immense pressure.

The former US Open champion produced some vintage moments in back-to-back points from 15-30 down to hold and secure a quality first set.

Momentum swung when they missed a chance to break Azarenka's serve at 3-3, with Stosur immediately broken and Sabalenka forcing a decider.

Both countries then produced the goods in a series of scintillating third-set rallies.

Australia grabbed the first break and Barty held firm for a 4-1 lead.

Stosur then held to love to get the hosts within one game and hit the winning volley on their third match point in the next game to clinch the tie.

"I could not have picked two more perfect athletes to contest this final rubber," Molik said.

"I'm just so proud of my team."

Both women will depart for the clay and grass courts of Europe before returning for a November home final in a city to be confirmed.

FED CUP SEMI FINAL

Sabalenka bt Stosur 7-5 5-7 6-3

Barty bt Azarenka 7-6 (7-2) 6-3

Barty bt Sabalenka 6-2 6-2

Azarenka bt Stosur 6-1 6-1

Barty/Stosur bt Azarenka/Sabalenka 7-5 3-6 6-2.

Australian Associated Press