As one of the all-time tennis greats, Roger Federer has done things on the court that we occasional-Sunday-morning players can only dream of. Well, now he's doing those things ... in the water.

To promote something called Fast 4 tennis, Federer and former U.S. Open and Wimbledon champ Lleyton Hewitt exchanged volleys while each was aboard a different boat in Sydney Harbor. You know, the type of thing you'd think want to try if you'd thrown back one too many while out for a day in the water. Except these guys pull it off, whereas you'd probably end up falling into the blue.