Authoritarian head of athletics cancelling street dash (6)

I believe the answer is:

fascia

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'cancelling street dash' is the definition.
I can't judge whether this definition defines the answer.

'authoritarian head of athletics' is the wordplay.
'authoritarian' becomes 'fasci' (I can't explain this - if you can you should believe this answer much more).
'head of' suggests taking the first letters.
The initial letter of 'athletics' is 'a'.
'fasci'+'a'='FASCIA'

Can you help me to learn more?

(Other definitions for fascia that I've seen before include "Shop sign" , "Car dashboard" , "Shopfront signboard" , "Surface over shop window" , "Flat strip on shop front for name etc" .)

I've seen this clue in The Telegraph.

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