Teenager Mika Stojsavljevic stunned Talia Gibson, ranked more than 200 places above her, in straight sets as Great Britain took a 2-0 lead over Australia in the Billie Jean King Cup.

The world number 275, making her debut in the competition, downed Gibson, 56th in the WTA rankings, 7-6 (7-4) 7-5 in the opening singles match in Melbourne.

Harriet Dart, ranked 173rd in the world, then fought back from a set down to beat Kimberly Birrell 4-6 6-3 6-3 in a little under two and a half hours.

A doubles and two reverse singles follow on Saturday, with Great Britain only needing to win one match to advance to the eight-team finals in Shenzhen, China, in September. The losers face a play-off in November.

Stojsavljevic, 17, is the second-lowest ranked player in a Great Britain team missing Emma Raducanu, Sonay Kartal, Katie Boulter, and Fran Jones – all of whom are ranked inside the world's top 100 for singles.

But the 2024 US Open junior champion was unfazed by her underdog status and the Australian crowd, holding her nerve to clinch the first set in a tie-break after letting a 3-1 lead slip.

She later saved five break points in the penultimate game of the match before converting her first match point.

"It feels amazing. I can't believe it. I can't even remember the last point," Stojsavljevic said. "I had amazing support from the side and managed to get through.

"Going into it, I knew she'd have the home ground. I'm grateful to the people supporting GB today.

"It was a good match. We have very similar games, both quite aggressive, so I'm happy I got through it."

Dart's meeting with world number 80 Birrell was characterised by service struggles, with no fewer than 16 breaks of serve and 27 break-point opportunities across the match.

After losing the opening set 6-4, the turning point for Dart came in the fifth game of the second when she held to 15 to end a run of four consecutive dropped service games. She then won three of the next five games, including a crucial second hold, to force a deciding set.

At 3-3 in the third, the 29-year-old broke Birrell for the eighth time before winning the next two game to secure the win and put Great Britain in control.