Lucifer's rival (5)
I believe the answer is:
match
I believe this is a double definition.
'lucifer's' is the first definition.
(synonyms)
'rival' is the second definition.
(synonyms)
(Other definitions for match that I've seen before include "Contest; pair" , "of little use when floodlights fail?" , "Equal - lucifer" , "Alliance" , "Equal contender" .)