Competed in the grand prix (3)
I believe the answer is:
ran
'competed' is the definition.
(running is a kind of competing)
'in the grand prix' is the wordplay.
'in' indicates a hidden word.
'RAN' can be found hidden inside 'grand prix'.
(Other definitions for ran that I've seen before include "Entered (a race)" , "Tore" , "Managed; operated" , "Hastened" , "Entered an election or managed" .)