Gamble on a character from Greece (4)

I believe the answer is:

beta

'character from greece' is the definition.

'gamble on a' is the wordplay.
'gamble' becomes 'bet' (betting is a kind of gambling).
'on' says to put letters next to each other.
'bet'+'a'='BETA'

(Other definitions for beta that I've seen before include "Second-class" , "Second Greek letter - beat that" , "Letter before gamma" , "Old character" , "Second highest grade of mark" .)

I've seen this clue in The Telegraph.

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