In his first outing since splitting with his long-time coaching team, Djokovic had to dig deep before eventually despatching Nicolas Almagro 6-1, 4-6, 7-5 in his second-round tie.
Nadal was also taken to three sets before seeing off Fabio Fognini 7-6 (7/3), 3-6, 6-4.
"My level of tennis was not so high today, but I managed to make it through the first round. It was uncomfortable. It was a really awful day. it was really windy," Nadal said.
"It's true I've been through some difficult days with the issue of my ear (infection), which cost me a little bit of general stability.
"I feel a little bit strange. But it's something that is getting better day after day."
