A topping trophy from one's victim? (5)

I believe the answer is:

scalp

I'm a little stuck... Click here to teach me more about this clue!

'a topping trophy' is the definition.
'scalp' can be an answer for 'trophy' (I've seen this before). I'm unsure of the 'a topping' bit.

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for scalp that I've seen before include "Skin with hair as trophy" , "Track, way" , "wants to resell theatre tickets" , "Cut hair very short" , "Skin covering top of the head" .)

I've seen this clue in the Evening Standard.

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