Nadal's forehand spin is reported at 3200 rmp (~335 rad/s)
Based on the tennis ball radius (0.066m), the energy of rotation is,
E = (1/2)*[(3/2)*M*(0.066)^2]*335^2 ~ 367*M
Where M is the mass of the ball and we have used the moment of inertia formula for a spherical shell (the tennis ball)...