Rome, Italy, 16 May 2014 | AFP

Chinese second seed Li Na defeated Samantha Stosur 6-3 6-1 to reach the quarterfinals 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 quarterfinal against Italian 10th seed Sara Errani, who beat Czech Petra Cetkovska 6-3 7-6(3).

In the men’s event, Rafael Nadal continued to search for his best clay form, surviving a shaky start to reach the quarterfinals and a date with Andy Murray.

The top seed beat Russian Mikhail Youzhny, winning 12 of the last 13 games in a 6-7(4) 6-2 6-3 win, which took almost three hours.

Murray and Nadal have not played each other for more than two and a half years, when Murray beat the Spaniard in a 2011 Tokyo final.

Less than 24 hours after being severely tested by Gilles Simon, Nadal found himself in trouble against Youzhny, who last won a set against the world number one back in 2008.

After spending 73 minutes in losing the opener, Nadal finally found enough form to take the victory at a tournament where he is looking to win for the eighth time.

“Andy will be a very tough match, he’s playing well, but I’m confident I can do it,” said Nadal, who added that if he does not take his chances against the Scot he “will be spending the weekend (at home) in Mallorca.

“I’ve had two long matches and I had hoped not to be on the court for so long, but that’s the way it is.”

Murray, who quit Rome with back problems a year ago and eventually required surgery, closed out a welcome win on his 27th birthday with an ace against Jurgen Melzer.

The Scot won 7-6(1) 6-4 to advance to his second straight clay quarterfinal after Madrid a week ago.

Meanwhile, 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.

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

But experience told him that the worry is not serious and should not affect his chances for Roland Garros, starting in 10 days time.

“It was difficult to give the intensity. I know my back, I just need some rest – maybe two days is enough,” he said.

In other women’s play, third-seeded Agnieszka Radwanska put out Italian veteran Francesca Schiavone, the 2010 French Open winner, 6-4 6-1, while sixth seed Jelena Jankovic beat Flavia Pennetta 6-2 6-3 and 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.

“I wasn’t sharp today but Ana played well,” said Sharapova. “I’m going to try to recover the next two or three days, settle down in Paris and get my body ready for a week of training.”