Speaking after the match, the Serb said: "Whenever you play Rafa, you know what to expect. You expect the toughest challenge possible on clay. I'm ready for that. I'm very happy that physically, mentally, emotionally I have been improving as the tournament was going on. Each day I feel better on the court, more confident.
"Of course, I will have to be on top of my game. I will have to be focused and motivated from the start to the end in order to have any chance of winning against Nadal.
"I need to have a very optimistic mindset in order to get a win. I'm not going out there to play my best; I'm going out there to win. That's how I'm going to feel tomorrow."
The pair have not played since the final of the French Open last year, which Nadal won in four sets.