Manchester United fans will admit Pep Guardiola has been at the forefront of evolving tactics. Guardiola made playing false nines fashionable, he introduced playing out from the back to England and, more recently, began to play central defenders in full-back roles. Other managers have followed Guardiola's tactical innovations and his former assistant manager Mikel Arteta picked up the central defender idea and ran with it at the Emirates.

Arteta has played Ben White out of position and Guardiola has changed the roles of Nathan Ake and Josko Gvardiol, with all three of those regularly playing as full-backs last season, providing extra defensive solidity on the wings and an advantage in build-up play. ALSO READ: Leny Yoro agrees to join United after Real Madrid interest ALSO READ: United distance themselves from Argentina scandal after 'racist' video Centre backs tend to be significantly better one-on-one defenders than traditional full-backs and that's an obvious positive, but playing a natural centre half as a full-back also allows teams to have a back-three in build-up, which helps to press high and defend counter-attacks. Playing central defenders out of position became a popular trend last season and Liverpool and Aston Villa played Joe Gomez and Ezri Konsa as their full-backs respectively.

The four teams who finished at the top Premier League all used the innovation, which suggests there's an advantage in doing so if implemented correctly. Now enter United and Erik ten Ha.