Word for trying to isolate an opponent player in association football

Solution 1:

The most usual term seems to be "man marking" as in this online article which discusses the difference between "man marking" and "zonal marking". Man marking is the practice of assigning one or more defenders to an attacker from the other side to prevent him from getting (or at least from keeping) the ball long enough to score while zonal marking is the practice of assigning defenders to areas of the pitch to deal with whatever threat comes to that area.

A more informal term would be "keeping him out of the game" but I don't know if there's a proper slang or jargon word for that. At one time the defender would have been said to have been "dogging" him as in dogging his footsteps or following him everywhere like a dog but the term "dogging" has come to mean sexual and voyeristic activity in remote sites these days (at least in Britain) so would not be used for close man marking on a football pitch for fear of misunderstanding and ribald comments.