Overwhelming victory or success (5,5)
I believe the answer is:
clean sweep
I believe this clue is a double definition.
'overwhelming victory' is the first definition.
(I've seen this in another clue)
'success' is the second definition.
(Other definitions for clean sweep that I've seen before include "Complete achievement of objectives" , "That's when you get everything going" , "Complete change; winning all the trophies" .)