Storm Sanders has scored the biggest singles win of her career, upsetting world No.18 Elise Mertens in a three-set contest at the Billie Jean King Cup Finals.
The stunning 3-6 7-6(5) 6-0 victory gives Australia an unbeatable 2-0 lead in its round-robin tie with Belgium.
Playing her first match in the Billie Jean King Cup competition, the 27-year-old Sanders produced a fearless display.
"It feels absolutely amazing," Sanders said. "I knew it was a tough ask coming out and playing Mertens, but I've played her before and definitely felt like I knew her game.
"We had a good game plan, which I went out and executed. To have the team on the sidelines was an awesome feeling and even though I lost the first set, I still felt like I was in control and doing all the right things. It's incredible to get the win."
The left-handed Sanders blitzed through the final set, hitting 11 winners to two to emphatically clinch a memorable victory.
"I don't think I've ever played a set that well in my life," she beamed after the match. "I don't think I made many unforced errors and was definitely hitting the ball well. I was just enjoying it and having fun out there."
The world No.131 hit 35 winners in total to record her third career victory against a top 50-ranked opponent - and first against a top-20 player.
"To do it in this moment, representing Australia, it is just the best feeling ever," Sanders said.
Sanders' career-best victory follows Daria Gavrilova's sensational return earlier today, upsetting world No.70 Greet Minnen 6-4 1-6 6-4 in her first professional match since February.
> READ: Gavrilova stuns Minnen at Billie Jean King Cup Finals
Belgium ended the tie on a positive note. With Mertens, the world's top-ranked doubles player, and Minnen teaming up to clinch the doubles rubber with a 6-2 6-4 victory against Sanders and debutante Ellen Perez.
Australia now plays Belarus in its second round-robin tie on Thursday, needing victory to earn a place in the knockout semifinals.
Billie Jean King Cup Finals
AUSTRALIA d BELGIUM 2-1
Daria Gavrilova (AUS) d Greet Minnen (BEL) 6-4 1-6 6-4
Storm Sanders (AUS) d Elise Mertens (BEL) 3-6 7-6(5) 6-0
Ellen Perez/Storm Sanders (AUS) lost to Elise Mertens/Greet Minnen (BEL) 2-6 4-6