The phrase "opposition defenders" refers to the players on the opposing team whose main job is to prevent the attacking team from scoring goals or advancing with the ball. They try to stop or block the attacking players' actions. Full definition
They do this by exploiting the space in front of them, making forward runs from a deeper position on the pitch, thus making it difficult for opposition defenders to mark them. (squawka.com)
He moves the ball quicker and faster leaving opposition defenders in their wake. (nigeriasoccernet.com)
He's always working the channels, pressing opposition defenders and trying to force an error or a back pass — all this,. (anfieldindex.com)