Relish time supporting America in game (5)
I believe the answer is:
gusto
'relish' is the definition.
('gusto' can be a synonym of 'relish')
'time supporting america in game' is the wordplay.
'time' becomes 't'.
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'america' becomes 'us' (abbreviation for the United States**).
'in' indicates putting letters inside.
'game' becomes 'go' (go is a kind of game).
't' put after 'us' is 'ust'.
'ust' inserted into 'go' is 'GUSTO'.
(Other definitions for gusto that I've seen before include "Great enjoyment, vigour" , "Zest, exuberance" , "Got us with great enjoyment" , "Zest, great enjoyment in doing" , "Zest, zeal" .)