Tailgate party backdrop (5)
I believe the answer is:
arena
'tailgate party backdrop' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for arena that I've seen before include "Where gladiators fought" , "Cheap Prom tickets" , "An era (anag.)" , "What the Colosseum was" , "place involving conflict?" .)