Australia's Fed Cup fortunes against Ukraine may hinge on Ashleigh Barty's reverse singles showdown with teen star Marta Kustyok after a mixed day for the home side in Canberra.
The Australians split Saturday's opening singles matches 1-1 with Barty claiming a tense first-up encounter with Lyudmyla Kichenok 4-6 6-1 6-4 after surviving an early scare.
However world No.26 Daria Gavrilova didn't fare so well, going down to the prodigious Kustyok in straight sets.
The 15-year-old took the first after an incredible eight breaks of serve, including seven in a row, and grew in confidence as the match went on.
In the end, Gavrilova was comprehensively outgunned by one of tennis' brightest young stars 7-6 (7-3) 6-3.
Captain Alicia Molik said she was confident Gavrilova could bounce back from the "shocker".
"It was a tough day (for Gavrilova) and I've been in that situation many times where I've had a bit of a shocker on day one, it's no big deal," she said.
Australia started out heavy favourites, with Ukraine missing world No.3 Elina Svitolina and 15-year-old Kustyok the team's highest ranked player at 185.
Barty said nerves played a role as she took to the court for her first Fed Cup singles rubber on home soil.
"I said to Mol (Australian captain Alicia Molik) straight after the national anthem, 'Mate I've got goosebumps'," Barty said.
"There was a little bit of jelly legs in the first couple of games; I felt like there was a fair bit of pressure on me today."
Her first set was filled with unforced errors as the players attempted to adjust to the temporary grass court at Canberra Tennis Centre.
Molik said Sunday's battle between Barty and Kostyuk would be fascinating.
"You've got a player (Barty) who's dealt with a lot of pressure and expectations and plays a mature game," she said.
"Marta probably hasn't been in a situation like this before, so tomorrow is a must-win for her and it's probably unfamiliar territory for her."
She was making her Fed Cup debut but Kustyok played with the poise and nous of an experienced veteran against Gavrilova.
She said she wasn't surprised by what she'd achieved.
"They say hard work pays off so I don't think it's a fairytale ... I'm playing good tennis.
"I don't think I have to be worse or better (against Barty) but I think I have to play a bit differently."
Gavrilova will take on world No.883 Kichenok following the Barty-Kostyuk clash at 11am AEDT on Sunday.
Barty will then team up with Casey Dellacqua if a doubles rubber is required against Ukraine's pairing of Nadiia Kichenok and 14-year-old Dasha Lopatetskaya.
