Liverpool manager Brendan Rodgers opted to play with three at the back in Sunday's contest against Manchester United. It took only 13 minutes for that decision to bite him in the backside.
United wing-back Antonio Valencia exploited the defensive ineptitude of Alberto Moreno by beating Joe Allen and running into the acres of space vacated by Moreno, before sending the ball across for Wayne Rooney to give the Red Devils an early lead.
So, so easy.