Coming first in race, bumping into a fellow competitor (7)
I believe the answer is:
arrival
'coming' is the definition.
(I've seen this before)
'first in race bumping into a fellow competitor' is the wordplay.
'first in race' becomes 'r' (1st letter of 'race').
'bumping into' indicates putting letters inside.
'fellow competitor' becomes 'rival'.
'a'+'rival'='arival'
'r' going within 'arival' is 'ARRIVAL'.
(Other definitions for arrival that I've seen before include "Appearance (at a place)" , "Achievement of destination" , "Someone who's just come" , "The A in ETA" , "Advent" .)