Fourteen-time Grand Slam champion Rafael Nadal believes that he faces a "tough" battle against Novak Djokovic in the semi-finals of the Monte Carlo Masters as he considers the Serbian a step ahead of everyone else.
Djokovic has only lost twice in 2015 and he could snatch his third Masters title on the bounce following victories in Indian Wells and Miami.
The world number one eased to the final four with a straight-sets win over Marin Cilic, while Nadal battled his way into the semis in three sets against David Ferrer.
"I was pleased with my level in this match," AFP quotes Nadal as saying. "David played very well, it was a high standard from both of us.
"The match with Novak will be tough - he is so far ahead of the rest of the players right now."
Nadal, who has struggled with injuries over the past year, has dropped a set in his last two matches in Monaco.
