The world number one went down 6-3 7-5 to his Spanish compatriot in the semi-finals of the tournament on Saturday.
"We know each other very well. I know what things he is doing well," Nadal told reporters. "When he's playing well, he's very dangerous on all the surfaces, but especially on this one, because it's probably the worst surface for me.
"I need to move quicker. I was slow. I felt that I [was] always a little bit late on the ball. David, he's quick and he plays inside the court and he puts you pressure on you all the time.
"If I move [better], I'm going to have the chance to hit the ball quicker and play with [fewer] mistakes."
Ferrer will face Novak Djokovic in the final on Sunday.