Try partnership for international contest (4,5)
I believe the answer is:
test match
'international contest' is the definition.
(I've seen this before)
'try partnership' is the wordplay.
'try' becomes 'test' (test is a kind of try).
'partnership' becomes 'match' (I've seen this before).
'test'+'match'='TEST MATCH'
'for' acts as a link.
(Other definitions for test match that I've seen before include "Ashes tie, perhaps" , "international - with 29a" , "International sports encounter" , "14 [NATIONAL] team meeting" , "may involve man dealing with maiden" .)