There is no doubt that he can beat Capdeville with eyes closed. All it takes is to stay more than 3-4 shots in the rally and he will make an UE. But it is obvious that David is testing his shots trying to hit winners with almost every shot.
He didn't really make any attempts to stay in rallies either, even on shots where they were just rallying around with the ball relatively close to him, so it's not like he was trying to save himself from doing some running. And hitting the ball completely flat, so that inevitably an error would come.