Contribution to run in the last inning? (5)
I believe the answer is:
ninth
'last inning?' is the definition.
(there are nine innings in baseball game)
'contribution to run in the' is the wordplay.
'contribution to' indicates a hidden word.
'NINTH' is hidden within 'run in the'.
(Other definitions for ninth that I've seen before include "Eg, Beethoven's choral symphony" , "Half-way hole?" , "Beethoven's "Choral", for example" , "Third of a third" , "Last of course to go out" .)