It's a question of logistics. They were able to present the trophy about 10 minutes after the end of the match....did they use a replica? Did they keep the trophy between the two venues and then chopper it in last minute to the winners?
Also, what if the venues were further apart? What would they have done then?
Was it a case of a helicopter on its way to Man Utd with the trophy and then had to do an emergency turn around and head to the city match?