To start with be embarrassed by the early enthusiasm (5,5)

I believe the answer is:

first flush

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'early enthusiasm' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'to start with be embarrassed by' is the wordplay.
'to start' becomes 'first' (synonyms).
'with' means one lot of letters go next to another.
'be embarrassed by' becomes 'flush' (I am not sure about this - if you are sure you should believe this answer much more).
'first'+'flush'='FIRST FLUSH'

'the' is the link.

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I've seen this clue in the Evening Standard.

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