Ally McCoist feels there was a ‘mismatch’ in midfield during last night’s clash between Arsenal and Chelsea. Arsenal moved three points clear at the top of the Premier League table with a convincing 5-0 win over Chelsea on Tuesday evening. Mikel Arteta’s side turned on the style in the second half after leading 1-0 at the break thanks to Leandro Trossard’s opener. Both Kai Havertz and Ben White were at the double, with Arsenal putting in a breathtaking attacking display at the Emirates. It was complete dominance from the Gunners after the break and it’s fair to say that was largely down to the…