Sam Stosur is backing Daria Saville to climb to fresh peaks and fill the void left in Australian women's tennis by Ash Barty's retirement.

And Saville herself has praised her one-time mentor Stosur for the inspiring pep talk over dinner that's helped her reach the third round of the French Open as the only Australian player left in the draw.

Nobody was happier than Stosur to witness the latest warming chapter in the Melbourne player's stirring comeback from injury as Saville outplayed double Wimbledon champion Petra Kvitova 6-4 6-2 at Roland Garros on Wednesday.

Yet even before she'd taken to the court for one of her best victories, the 2011 US Open champ Stosur, who's on doubles duty in Paris, was predicting great times ahead for the rejuvenated 'Dasha'.

"I think Ash covered up a few holes, because now she's gone, we only have Ajla (Tomljanovic) in the top 100 at the moment," Stosur, when asked about the current state of women's tennis in Australia, said.

"All of a sudden, things are not looking so great.

"But I think Dasha is going to get back up there soon. It's great she is back playing and healthy again, touch wood, because she has been through a really rough couple of years.

"If she can stay fit, she can absolutely push to where she was."

For a brief time five years ago when the 2010 Roland Garros finalist Stosur's star was beginning to wane and Barty's was just really starting to shine, Saville - at the time, Daria Gavrilova - was Australia's No.1.

"Sam always kind of mentored me, and she's someone I always look up to," Saville said.

"I was with her and Stubbsy (Rennae Stubbs) in Strasbourg (the tournament before the French Open) and we went out to dinner after I lost (narrowly to Anna-Lena Friedsam).

"Basically, they said, 'don't be so hard on yourself' and pointed out positives. They thought I was losing focus and they kind of mentored me.

"Sam was like, 'this is what I normally do', so I said OK, 'I'm going to try it in Roland Garros'."

Stosur was egging her on to follow "the 3Cs - clarity, composure and commitment" - qualities that Saville demonstrated in abundance against Kvitova to set up a third-round clash with Martina Trevisan, an old Italian friend from their teenage days.

And the 38-year-old Stosur was apparently herself still following the mantra as she won her opening doubles match with her new playing partner Latisha Chan.