Wearing thong, enthralling the Spanish with flash finally (2,3,4,3)

I believe the answer is:

in the long run

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'finally' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for in the long run that I've seen before include "At the end of the day" , "marathon effort" , "Eventually" , "Finally" , "sooner or later" .)

I've seen this clue in The Telegraph.

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