The former Red Devils boss was in the stands as Louis van Gaal’s men made it three wins in a row to cap a fine week for the club.
And Sir Alex clearly approved of the performance and the win, if these photos are anything to go by.
United went ahead in the 29th minute when Marcus Rashford fired into the top corner from inside the box – and the teenager made it 2-0 shortly after when he blasted home from close range on his Premier League debut.
The north London side pulled a goal back when former Red Devils Danny Welbeck headed Mesut Ozil’s free-kick into the near post before half-time.
However, Ander Herrera’s deflected shot restored Manchester United’s two-goal lead in the 65th minute.
Ozil pulled a goal back for the Gunners in the 69th minute but the north London side were unable to conjure an equaliser.
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