In the past five years both Manchester United and Arsenal have bid farewell to legendary managers but while the former have struggled since the departure of Sir Alex Ferguson in 2013 the latter have enjoyed a resurgence since Unai Emery replaced Arsene Wenger this summer.

As they prepare to meet on Wednesday night, James Ducker looks at the mistakes United made and Sam Dean analyses how Arsenal learnt from them.

Succession planning

David Gill had informed Sir Alex Ferguson that he intended to step down as Manchester United chief executive before the manager communicated his decision to retire in the summer of 2013, but the simultaneous loss of the club’s two figureheads was a grave error of judgment by the club.

United seemed too concerned about keeping Ferguson’s retirement under wraps than conducting a strategic review of the ramifications of his exit. Ed Woodward spent some time shadowing Gill, but the jump from running United’s commercial arm to steering the ship was too much, too soon, and was compounded by the absence of football expertise around him and stay-away owners.

Arsenal’s planning for the post-Arsene Wenger era began well before Wenger had left the club, with no vacuum created as United did when Gill departed. The behind-the-scenes structure was overhauled by the appointments of head of football relations Raul Sanllehi, head of recruitment Sven Mislintat and contract negotiator Huss Fahmy last year.