Club perhaps provided source of financial capital (7)
I believe the answer is:
cardiff
'capital' is the definition.
(I know that Cardiff is a national capital)
'club perhaps provided source of financial' is the wordplay.
'club perhaps' becomes 'card' (clubs is a playing card suit).
'provided' becomes 'if' (eg 'provided it's sunny' means 'if it's sunny').
'source of' says to take the initial letters.
The first letter of 'financial' is 'f'.
'card'+'if'+'f'='CARDIFF'
(Other definitions for cardiff that I've seen before include "Welsh capital" , "Place in Wales" , "Capital of Wales" , "Capital on the Taff" , "City on the Taff" .)