Centre back is the easiest position to play on the field.. Luton were already 3-0 up and the game won by then. so don't be counting too many chickens..
While no position in professional football is easy, I'd say CD is one of the hardest. No position requires such a balance of strength, skill, experience, reading of the game, pressure. It's so difficult the world's best defenders don't emerge until their late 20s such are the demands on experience and decision making. and if it were so easy why haven't England produced a good one since Terry and Rio retired.