Extremely good-looking NI footballer keeps playing there (8)

I believe the answer is:

bonniest

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'playing there' is the definition.
I can't tell whether this defines the answer.

'extremely good-looking ni footballer keeps' is the wordplay.
'extremely good looking' becomes 'on' (I can't justify this - if you can you should believe this answer much more).
'footballer' becomes 'Best' (George Best).
'keeps' is an insertion indicator (inserted letters are kept inside).
'on'+'ni'='onni'
'onni' going within 'best' is 'BONNIEST'.

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(Another definition for bonniest that I've seen is " Most healthy-looking baby".)

I've seen this clue in The Independent.

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