Originally Posted by Topspin Forehand
In Barcelona, Nadal was playing great tennis. His shots were penetrating and kicking up. It was like that the whole tournament. He hasn't been getting that kind of action on his shots consistently the rest of the clay court season. I blame the balls and partially the schedule he set up for himself.
Barcelona uses exactly the same balls as all the clay masters.
Differences are more about conditions than anything. If it's damp, the ball picks up moisture and clay, and becomes heavy - for example, in the Rome final.