Toronto: World number one Rafa Nadal was made to work as he launched his North American hardcourt campaign with a battling second round win at the Toronto Masters.
Under a floodlit center 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 tiebreak that Nadal took 14-12, matching the longest tiebreak 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 tiebreak 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 awhile," Nadal told reporters. "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 favor even though I would like it."
A winner in Canada in 2007, Djokovic appeared uncomfortable the moment he stepped onto the court and eventually summoned for the trainer after going down a break in the second set.
Struggling for air, Djokovic appeared ready to throw in the towel but hung on as Benneteau kept up the pressure.
Desperate to keep the match from going to a third set, a faltering Djokovic finally finished off his French opponent on the fifth match point with an overhead slam.
Briton Andy Murray followed Djokovic onto a scorching center 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 Murray, who needs a good result in Toronto to keep Swede Robin Soderling from replacing him as world number four.