Apple overtakin' rivals at the last moment (6)
I believe the answer is:
pippin
'apple' is the definition.
(pippin is a kind of apple)
'overtakin' rivals at the last moment' is the wordplay.
I cannot really understand how this works, but
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pippin that I've seen before include "Variety of eating apple" , "excellent example" , "Hobbit, friend of 1 across" , "beauty" , "fruit" .)