Nadal and Djokovic survive tests in Toronto

World number one Rafa Nadal was made to work and number two Novak Djokovic had to sweat as they launched their North American hardcourt campaigns with battling second round wins at the Toronto Masters on Wednesday.

Under a floodlit centre court, Nadal was put to the test by Stanislas Wawrinka, needing two hours and 20 minutes and all his weapons to put away the stubborn Swiss 7-6 6-3.

The opening set took a gruelling 92 minutes before ending in a pulsating tie-break that Nadal took 14-12, matching the longest tie break of his career.

In five meetings with Nadal, Wawrinka had never taken a set off the muscular Mallorcan or claimed a victory over any world number one in six tries. Wawrinka, who partnered Roger Federer to a doubles gold medal at the Beijing Olympics, looked determined to end both streaks and kept the pressure on Nadal.

But Nadal, playing his first match since his Wimbledon victory in July, never panicked and seized control of the tie-break and the second set to remain on course for a third Canadian title.

"I had a little bit of everything today being my first match after a while," said Nadal. "I had difficult moments, I had moments when I played well. I did a little bit of everything."

While Nadal skipped off the court looking as if he could keep playing, Djokovic could barely stand after a gritty 7-5 7-5 win over Frenchman Julien Benneteau in sweltering midday conditions. Drained by the sauna-like conditions, the Serb was left slumped over the net gasping for breath after finally finishing off his French opponent in a little over two hours.

"I have said before, I will never risk my health to win and I was really on the edge," said Djokovic, who has struggled with heat-related issues throughout his career.

"If your body gives you signs that something bad is going on you have to do something ... no one can turn off the sun and do me a favour even though I would like it."

Andy Murray followed Djokovic onto a scorching centre court and had to overcome a slow start before speeding past Belgian Xavier Malisse 7-5 6-2.

It was a positive start to an important tournament for the Scot, who needs a good result in Toronto to keep Swede Robin Soderling from replacing him as world number four. Argentina's David Nalbandian came back from a set down to defeat No 5 seed Soderling 4-6 6-4 6-1

Meanwhile, second seed Caroline Wozniacki suffered a surprise third-round exit to France's Marion Bartoli 6-4 6-1 in the Cincinnati Open. In another upset, Russian sixth-seed Vera Zvonareva went out in straight sets, 6-4 6-3, to Italian Flavia Pennetta as the sunshine returned after Wednesday's rain.

Serbia's Ana Ivanovic again looked in good form as she confidently defeated Russia's Elena Vesnina 6-0 6-3.Ivanovic could face compatriot Jelena Jankovic in the last eight, if Jankovic beats Uzbek qualifier Akgul Amanmuradova.