This one's a bit convoluted but you're kinda there.
Before final whistle while staying back, Gunners pass is saved in the box of Gordon Banks (9)
Before final - this part goes at the end of the clue and the rest goes before it
whi (st) le while staying ('while' is ceasing to be) leaving st - back = reverse = ts
Gunners = RA + pass = die
saved in = container indicator
the box of Gordon = GN
Banks = Def
G RA die N ts