Lose and you won't get your hands on the cup - it's advice a manager gives the team before getting fired (5,7)

'manager gives the team before getting fired' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'lose and you won't get your hands on the cup it's advice a' is the wordplay.
I cannot quite see how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
'advice' could be 'warning' (warning is a kind of advice) and 'warning' is found within the answer.
'a' is present in the answer.
The remaining letters 'fil' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?