Maria Sharapova has stayed on course for a second French Open title by reaching the quarter-finals at Roland Garros, but two new-wave hopefuls are lining up to take her down.

The Russian seventh seed, and tournament favourite since the top three seeds all lost, produced a typically battling performance to overcome Australian veteran Samantha Stosur 3-6 6-4 6-0 in a late-finishing fourth-round tie.

Sharapova, who won the French Open in 2012 to complete a sweep of all four Grand Slam titles, grabbed a break to open the decider and with the Stosur challenge visibly wilting, she turned on the power to reach her third straight quarter-final in Paris.

“I am so happy to be back in the quarter-finals as it is such a special tournament for me,” she said.

“I just hope I can raise my level and play even better in the second week.”

Waiting for her there in the last eight will be 20-year-old Spaniard Garbine Muguruza who had little difficulty seeing off the challenge of French wildcard Pauline Parmentier, winning 6-4 6-2 on the Roland Garros centre court.

It was Muguruzu who produced the shock of the tournament to date with a second-round upset of top seed and defending champion Serena Williams.

And if she fails to get the better of Sharapova, the Russian could be facing another 20-year-old in the semi-finals in the shape of fast-rising Eugenie Bouchard.

The Canadian crushed German eighth seed Angelique Kerber 6-1 6-2 to reach her second Grand Slam quarter-final.

Her first came in Australia in January when she made it through to the semis.

The youngest player left in the draw, Bouchard, seeded 18, had made a slow start to her two previous matches, but she hit the deck running against the big-hitting Kerber, a Roland Garros quarter-finalist in 2012.

Bouchard, who won her first career title in Nuremberg in the week before Roland Garros started, said that she was confident she could go deeper into the tournament.

“I mean, I’m confident, you know, and I really believe in my skills. I believe I can play with the best girls out there,” she said.

Standing in Bouchard’s way for a potential matchup against Sharapova is Spain’s Carla Suarez Navarro, who proved too good for 21-year-old Croatian Ajla Tomljanovic, winning 6-3 6-3.

The highest-ranking seed left is fourth-ranked Simona Halep, a 22-year-old Romanian who will attempt to reach the quarter-finals on Monday with a match against 21-year-old American Sloane Stephens.