Cancel tickets, including football team (6)
I believe the answer is:
celtic
'football team' is the definition.
(I've seen this before)
'cancel tickets including' is the wordplay.
'including' indicates a hidden word.
'CELTIC' can be found hidden inside 'cancel tickets'.
(Other definitions for celtic that I've seen before include "Roy Keane's team on the fringe" , "Scottish club" , "The Irish are part of the race" , "Language group containing 14 & 15 across" , "The race of ancient Gaels" .)