Match against, to start with, in the competition (7)
I believe the answer is:
contest
'competition' is the definition.
('contest' can be a synonym of 'competition')
'match against to start with' is the wordplay.
'match' becomes 'test' (test match is a kind of match**).
'against' becomes 'con' (I've seen this before).
'to start with' is a charade indicator (letters next to each other).
'test' after 'con' is 'CONTEST'.
'in the' acts as a link.
(Other definitions for contest that I've seen before include "Tournament" , "Oppose - competition" , "Competition or conflict" , "Competition; dispute" , "Match" .)