The Red Devils lost 1-0 to Chelsea FC in the FA Cup final at Wembley last weekend after Eden Hazard netted a first-half penalty to secure their second trophy in successive seasons under Antonio Conte.
Manchester United ended up in second place in the Premier League table ahead of rivals Tottenham Hotspur, Liverpool FC, Chelsea FC and Arsenal to secure their best finish since 2013.
The Red Devils, though, finished 19 points adrift of runaway Premier League champions Manchester City to highlight the widening gap between the derby rivals under Pep Guardiola and Mourinho.
Manchester United suffered a surprise 2-1 loss to Spanish side Sevilla in the Champions League round of 16 and Bristol City were 2-1 winners against Mourinho’s side in the League Cup semi-final.
Former Arsenal star Merson believes Manchester United need five signings in the summer transfer window to close the gap between themselves and defending Premier League champions Manchester City.
Manchester United haven’t won the Premier League title since 2013 when Sir Alex Ferguson got his hands on his 13th and final top flight crown.
The Red Devils won the Europa League and the EFL Cup under Mourinho last term.
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