Battle knight — try to follow horse (7)
I believe the answer is:
marengo
'battle' is the definition.
(Marengo is an example)
'knight try to follow horse' is the wordplay.
'knight' becomes 'N' (chess abbreviation).
'try' becomes 'go' (both can mean an attempt).
'to follow' is a charade indicator (letters next to each other) (some letters go after or follow others).
'horse' becomes 'mare' (mare is a kind of horse).
'n'+'go'='ngo'
'ngo' put after 'mare' is 'MARENGO'.
(Other definitions for marengo that I've seen before include "Battle of the Napoleonic Wars in Piedmont" , "vegetables and wine" , "Napoleonic victory in 1800" , "battle fought in Italy" , "Napoleon's horse" .)