Ball machine. That is right. Get the highest-end ball machine and program it to pitch the ball with spin, pace and trajectory resembling Nadal. If there is no such machine, pay a robotics company to develop one. And practise, practise, practise. No one else can match the forehand to backhand lefty topspin of Nadal. Ball machine is the best bet. To match Nadal's retrieving capabilities program the machine to pitch the next ball around the time Nadal would return the shot. And keep doing this over and over again. Get rid of Higueras and spend the money on a ball machine. What Federer lacks is not strategy, but simply the ability to be consistent with the ball (no shanking) when pressurized by Nadal. Otherwise Nadal just says "Shank you very much" and pockets the point.