Contest is equal (5)
I believe the answer is:
match
This clue is a double definition.
'contest' is the first definition.
(match is a kind of contest)
'equal' is the second definition.
('match' can be a synonym of 'equal')
'is' is the link.
(Other definitions for match that I've seen before include "Go together" , "Fixture - fit with - smoker's aid" , "Contest; correspond" , "of little use when floodlights fail?" , "Marriage; game" .)