Claim: Mirka Federer was a player of a ball sport.
Evidence: Miroslava `` Mirka '' Federer -LRB- born Miroslava Vavrincová on 1 April 1978 , later Miroslava Vavrinec -RRB- is a Slovak-born Swiss former professional tennis player.
The object of the game is to play the ball in such a way that the opponent is not able to play a valid return.