Chinese second seed Li Na defeated Samantha Stosur 6-3 6-1 to reach the quarter-finals of the ATP-WTA Rome Masters on Thursday, turning the tables in a long-running rivalry.

Stosur, a 2010 Roland Garros finalist, had beaten world No.2 Li in all six of their previous meetings going back to 2007.

The victory was her second straight over an Australian opponent after defeating qualifier Casey Dellacqua in the previous round.

But China’s top female athlete made inroads against Stosur’s one-way scoreline with her first victory, achieved in 68 minutes with five breaks of the 30-year-old Stosur.

“In the last six matches I tried to control the ball, but she was able to get a lot of chances,” said 32-year-old Li who will play a quarter-final against Italian 10th seed Sara Errani, who beat Czech Petra Cetkovska 6-3 7-6 (7-3).

In the men’s event, Monte Carlo champion Stanislas Wawrinka joined fellow Swiss Roger Federer on the scrapheap as back pain resulted in a 5-7 6-2 6-3 loss to 15th seed Tommy Haas.

The 36-year-old has now won both of his matches with Wawrinka, a 2008 finalist at the Foro Italico.

Andy Murray, who quit the event with back problems a year ago and eventually required surgery, closed out a welcome win over Jurgen Melzer with his sixth ace for a 7-6 (7-1) 6-4 result which puts him into his second straight clay quarter-final after Madrid a week ago.

But he’ll have to contend with top-ranked Rafael Nadal who was pushed to three sets for the second consecutive match.

The Spaniard dropped behind a set and a break against Mikhail Youzhny of Russia, then won 11 of the final 12 games to prevail 6-7 (4-7) 6-2 6-1 on another windy day at the Foro Italico.

Germany’s Haas ended with seven aces to eight for Wawrinka, who could not hold onto leads throughout the two-hour contest. The winner produced 32 winners while Wawrinka struck 40 unforced errors.

Wawrinka said that after playing a match in the chill two days earlier, he started having back problems.

But experience told him that it should not affect his chances for Roland Garros starting in 10 days.

“I know my back, I just need some rest – maybe two days is enough – but I’m not worried about it,” he said.

Canadian eighth seed Milos Raonic reached his first Rome quarter-final with a defeat of French 11th seed Jo-Wilfried Tsonga 7-6 (7-5) 6-4.

In other women’s play, third-seeded Pols Agnieszka Radwanska put out Italian veteran Francesca Schiavone, the 2010 French Open winner, 6-4 6-1.

Ana Ivanovic handed Maria Sharapova her first loss of the spring clay season as she beat the Russian eighth seed 6-1 6-4.

Sharapova had won back-to-back titles in Stuttgart and Madrid, compiling a dozen straight victories.

Ivanovic, the 2008 Roland Garros winner and world number one, had won just two of 10 previous meetings with the four-time grand slam champion, the last seven years ago at a Roland Garros semi-final.