Arsenal boss Arsene Wenger says the shift to 4-3-3 has meant more quality is demanded from centre-backs.

Wenger believes the move away from 4-4-2 has had a major effect on central defenders.

"[The role] is changing to increase the shape of the teams," he said. "The traditional shape of football was 4-4-2 and the new shape is to have one isolated striker.

"In a 4-4-2 system, the two full backs get the ball first because the two strikers are in the middle and the two centre backs are marked so the keeper's first solution is to the full backs.

"In the modern game, the two full backs are marked by two wingers or wide midfielders and the first available player are the centre backs as they are playing two against one.

"That means the importance of that technical quality is much more important. Even if they are less good defensively, they have less to deal with than two against two - they are always in a two against one situation.

"The start of the game is with the centre backs nowadays, and that's why that technical ability has suddenly become important."