Grounded mischievous David, famously (8)

I believe the answer is:

underdog

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'david famously' is the definition.
I can't tell whether this defines the answer.

'grounded mischievous' is the wordplay.
'mischievous' is an anagram indicator.
'grounded' is an anagram of 'UNDERDOG'.

Can you help me to learn more?

(Other definitions for underdog that I've seen before include "No drudge (anag.)" , "One thought unlikely to win" , "One thought to have little chance of winning" , "Loser; subject" , "Such is unlikely to succeed" .)

I've seen this clue in the Sydney Morning Herald.

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