A player who operates as both a defender and a winger, usually in a back-five system. Has to cover the entire flank, from their own corner flag to the opposition's byline. Requires the lungs of a marathon runner and the crossing ability of a winger. A formation lives and dies on its wing-backs.
"He's sprinted the full length of the pitch to deliver that cross and now he's tracking back. Wing-backs don't get enough credit."