After playing on the practice court for an hour or two, they started getting serious...
...And yes, also called Football-Tennis. A similar sport called Sepak Takraw exists, but the ball cannot touch the ground and is *far* more acrobatic.
According to Rafael Nadal's official website:
"During his training session yesterday, Rafa Nadal and his PR Manager, Benito thought it would be fun to team-up to play a mini-football match against Novak Djokovic and Marian Vajda. Sadly for Rafa and Benito (who said it was his fault they lost), their opponents had no mercy on them."