American teenage tennis star Coco Gauff can help "change the world for the better"," says 18-time Grand Slam champion Martina Navratilova.

At a peaceful protest in Florida last month, Gauff urged people to vote and speak out against racism.

"I smile so much when I see the reach she already has now, and she will have in the future," said Navratilova.

She told BBC Radio 4's Today Programme: "She is just so poised on and off the court, she was brought up with great qualities and it shows how she plays and it shows how she's active now politically.

"She's one of those people that can change the world for the better, and she seems to want to do that."

Navratilova, 63, says it is "essential" sport stars use their platforms as they can see "how much politics can affect their lives and their freedoms".

"Sport has always been at the forefront of social change," she added. "And now it can be that again with Black Lives Matter and just equality for all.

"Tennis has had its share of obstacles, but I think overall, we've been at the forefront of social change and it seems like now with Coco Gauff, leading the charge, we're still there."

Meanwhile, Navratilova says tennis needs to "play it safe" after several players revealed they had coronavirus after playing at Novak Djokovic's Adria Tour competition.

Djokovic, Grigor Dimitrov, Borna Coric and Viktor Troicki have all tested positive for Covid-19.

"They tried to do a free-for-all, and we know how it ended up," added Navratilova.

"Right now, we just need to play it safe. I applaud everybody that's trying to find different ways to put on an event. But clearly that was not the way to go."