Pulled back a bit but ruled soundly (6)
I believe the answer is:
reined
'pulled back a bit' is the definition.
(to rein in is to pull back or control)
'ruled soundly' is the wordplay.
'ruled' becomes 'reigned' (reigning is a kind of ruling).
'soundly' indicates a 'sounds like' (homophone) clue.
'reigned' is a homophone of 'REINED'.
'but' is the link.
(Other definitions for reined that I've seen before include "Stopped or slowed a horse" , "Pulled in, checked progress" , "Restrained" .)