Succeeding in chasing? (5)
I believe the answer is:
after
This clue is a double definition.
'succeeding' is the first definition.
(thesaurus)
'chasing?' is the second definition.
(I've seen this before)
'in' acts as a link.
(Other definitions for after that I've seen before include "since" , "Subsequently" , "Chasing" , "Searching for" , "In the time following" .)