Chelsea interim head coach Calum McFarlane described a “crazy 24 hours” after he was asked to step up from the under-21s to lead the first team away to Manchester City on Sunday.The former Southampton youth coach was called into the club’s Cobham training centre at around lunchtime on Thursday shortly after the decision was taken to part company with Enzo Maresca, and told he would be in charge at the Etihad.