Luke Shaw struck Arsenal 's FA Cup winner against Manchester United . He celebrated the goal and received a mixed reception when substituted . Maroune Fellaini was United 's best player but Danny Welbeck struggled . Man Utd and Arsenal SPECIAL : Are fans right to question Louis van Gaal ? READ : Twitter reacts to Manchester United 's FA Cup exit .
Danny Welbeck struck Arsenal 's FA Cup winner against Manchester United . He celebrated the goal and received a mixed reception when substituted . Maroune Fellaini was United 's best player but Luke Shaw struggled . Man Utd and Arsenal SPECIAL : Are fans right to question Louis van Gaal ? READ : Twitter reacts to Manchester United 's FA Cup exit .