Worked fast, was winning after cycling thus (7)
I believe the answer is:
hustled
'worked fast' is the definition.
(to hustle is to work hard or quickly)
'was winning after cycling thus' is the wordplay.
'was winning' becomes 'led' (to lead can mean to be winning a game).
'after' means one lot of letters go next to another.
'cycling' indicates anagramming the letters.
'thus' is an anagram of 'hust'.
'led' put after 'hust' is 'HUSTLED'.
(Other definitions for hustled that I've seen before include "Shoved roughly" , "Jostled" .)