Stosur, whose first-round match with Japan’s Misaki Doi was played across two days due to persistent rain which forced a backlog of clashes, was able to get through just 44 minutes of her fourth-round clash with sixth seed Simona Halep overnight.

The 21st seed is down a break and trails 5-3 in the first set against Halep, with a quarter-final spot against either world No.2 Agnieszka Radwanska or Bulgaria’s Tsvetana Pironkova on the line.

Radwanska held a healthy 6-2 3-0 over Pironkova before their match was also halted due to rain.

Play will resume this afternoon, Australian time, although more rain is forecast.

A late switch took the pair from from the showpiece Court Philippe Chatrier to court one, the match finally getting underway in front of a few dozen fans at 7.51pm with the threat of further rain ever present.

Stosur, who hailed her third-round victory over 11th seed as good as any from her previous deep runs at Roland Garros, again started strongly against Halep.

The 32-year-old hit 12 winners as her power game caused problems for her younger, more-fancied opponent.

But the high-risk approach of going for winners had its drawbacks as Stosur racked up just as many unforced errors (12) compared to Halep’s six.

Stosur squandered three break point chances with Halep serving down 3-2, and bolstered by her big hold the Romanian immediately broke the Australian to take a 4-3 lead and the early advantage.

Sensing the importance of winning the break back before the rain hit, Stosur unleashed on Halep’s serve in the following game – but it was to no avail as the 24-year-old produced some extraordinary tennis to hold.

Meanwhile, Andy Murray moved ominously into the French Open quarter-finals for the sixth time in his career with a clinical 7-6 (11-9) 6-4 6-3 defeat of American John Isner.

The second seed began the tournament scraping through back-to-back five-setters but has been a model of efficiency since and has his eyes fixed firmly on a first title at Roland Garros.

Isner took a 0-5 career record against Murray on to a murky Court Suzanne Lenglen but he stuck manfully to his task in the first set, denying the Briton the slightest whiff of a break.

The 15th seed had three set points in the tiebreak, the first of which, when serving at 6-5, he will be rueing.

Murray reacted superbly to return a booming first serve and Isner then failed to make the most of an inviting mid-court forehand, giving the Briton the chance to ram a backhand past him as he advanced to the net.

Three-times Roland Garros semi-finalist Murray converted his second set point when Isner hit a forehand wide.

After a rain delay, the second set proved another tight tussle before Isner cracked under pressure at 4-5 — Murray breaking for the first time to move two sets clear with the help of a delightful angled drop shot.

It was routine after that for Murray who will play either Frenchman Richard Gasquet or Kei Nishikori next.

Reigning Champion Stan Wawrinka lit up a gloomy Roland Garros with his lurid day-glo yellow shirt as he reached the quarter-finals with a dazzling 7-6 (7-5) 6-7 (9-7) 6-3 6-2 win over Serbia’s Viktor Troicki.

In an entertaining match featuring between the leg shots, a mid-match rally with a ballboy and an array of blinding backhand winners from Wawrinka, the Swiss third seed chalked up his fifth successive win over Troicki when the Serb netted a backhand.

The win earned Wawrinka an eighth successive win on clay, following his triumph in the Geneva tournament last weekend, but more importantly it allowed him to set up a quarter-final meeting with unheralded Spaniard Albert Ramos-Vinolas.

Troicki kept Wawrinka on his toes during the first half of the contest, with the Swiss winning the first set on his eighth set point before the Serb bagged the second set on his fifth.

But all the running around he did in the first two sets caught up with Troicki midway through the third set as called on the trainer to manipulate his hip.

The treatment failed to have the desired effect and he fell to a 20th successive defeat against top-three opponents.

Subdued eighth seed Milos Raonic’s French Open came to an abrupt halt when he was swept aside 6-2 6-4 6-4 by Ramos-Vinolas.

The big-serving Canadian could make little impression against the dogged, 28-year-old left-hander who finished the contest with an angled smash on his third match point.

-AAP, Reuters