Came first in two nations (3)
I believe the answer is:
won
'came first' is the definition.
(I've seen this before)
'in two nations' is the wordplay.
'in' indicates the answer is hidden within the clue.
'WON' can be found hidden inside 'two nations'.
(Other definitions for won that I've seen before include "little cash in Korea" , "Triumphed" , "Gained a victory" , "and 26: Chinese dumpling" , "Succeeded, conquered" .)