Frank Spencer's first in competitions (5)
I believe the answer is:
opens
'competitions' is the definition.
(open is a kind of competition)
'frank spencer's first' is the wordplay.
'frank' becomes 'open' (synonyms).
'spencer's first' becomes 's' (1st letter of 'spencer').
'open'+'s'='OPENS'
'in' is the link.
(Other definitions for opens that I've seen before include "Takes the cover off" , "Unlocks" , "Launches" , "Provides access to" , "competitions welcoming all-comers" .)