Having taken the lead through Marcus Rashford, the scores were level at the break thanks to an Eddie Nketiah goal.
An action-packed second half saw Bukayo Saka put the hosts ahead, before a Lisandro Martinez header levelled things up, but it was to be Nketiah who would make the decisive impact in the closing stages.
Below are the key discussion points from our trip to London...
DESERVED MORE
The league position of the Gunners is testament to the different proposition they have posed teams this season and, on another day, it might have been United to find a winner.