One overturned in a race? (3)

I believe the answer is:
car
'a race?' is the definition.
(car race is a kind of race)
'one overturned in' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'overturned' becomes 'cr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'a' inserted into 'cr' is 'CAR'.
Can you help me to learn more?
(Other definitions for car that I've seen before include "Passenger vehicle" , "estate, perhaps" , "Automobile" , "One for the road?" , "Conveyance" .)
