Match official on pitch current couple occasionally upset (7)
I believe the answer is:
lucifer
'match' is the definition.
(synonyms)
'official on pitch current couple occasionally upset' is the wordplay.
'official on pitch' becomes 'ref' (short for referee).
'current' becomes 'i' (symbol for electric current).
'occasionally' means one should take alternating letters.
'upset' says the letters should be written in reverse.
The alternate letters of 'couple' are 'cul'.
'ref'+'i'+'cul'='reficul'
'reficul' in reverse letter order is 'LUCIFER'.
(Other definitions for lucifer that I've seen before include "Light" , "Rising star" , "Prince of Darkness" , "Rebellious angel; a match" , "Venus" .)