On one of Murphy Jensen's Tennis Channel specials before Wimbledon '06, he interviewed Kristof Vliegen. He mentioned in the interview that Kristof is widely regarded as the best soccer player on tour. He even challenged Vliegen to a quick one-on-one as Murph protected 2 cones spaced a few feet apart. Vliegen pretty much juke-and-jived him and scored with ease.
Nadal has also been shown on TTC playing beach soccer in Mallorca and he scored a sweet goal where he kicked the ball up in the air, spun 180 degrees, and kicked it past the goalie. He has skillz. BTW ... he was butt-picking while playing soccer as well.