Fellow takes Frenchman to be Victor (5)
I believe the answer is:
champ
'be victor' is the definition.
(I've seen this in another clue)
'fellow takes frenchman' is the wordplay.
'fellow' becomes 'chap' (both can mean a man).
'takes' indicates putting letters inside.
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
'chap' going around 'm' is 'CHAMP'.
'to' is the link.
(Other definitions for champ that I've seen before include "boxer who is top dog?" , "Bite - victor (abbr)" , "use teeth?" , "first place" , "Munch (at the bit?)" .)