England's Jenna Randall won silver in the synchronised swimming solo event with a superb freestyle routine at the Melbourne Aquatics Centre.
Randall just missed out on bronze in the duets
Randall, 17, from Surrey, finished just behind Canada's Marie Boudreau, while Australia's Irena Olevsky won bronze.
She said: "I would have been happy with any medal, but to win silver in my first major meet is amazing."
In the duets event, Randall and Olivia Allison, 16, from St Albans, finished just outside the medals in fourth.
The pair were third after Saturday's technical duets routine, but slipped down a position after the freestyle. Allison said: "We are obviously disappointed at missing out on the bronze.
"But it's our first international competition, we are both very young and have still got a lot to learn. This has been a fantastic experience."
Coach Adele Carlsen added: "I think they both did very well as they are both still juniors and were against some very experienced girls.
"I'm gutted we lost out on the bronze, they had a great swim but the timing was a little off in parts.
"Both girls are great talents for the future and Jenna's outing in the solo was just superb."