In boxing a counter puncher is dangerous even to top fighters.
This is also true in tennis.
This definition of the term in boxing could easily fit a tennis player and it would not fit as a definition of a pusher.
Counter punchers are tactical, defensive fighters who rely on opponent mistakes in order to gain an attacking advantage to get score cards or the chance of a knockout. They use their well-rounded defensive skills to avoid or block shots in order to immediately place well-timed punches on opponents who have lost their guard.