Underdog victories (6)
I believe the answer is:
upsets
'underdog victories' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for upsets that I've seen before include "Disapppointments" , "Unexpected results" , "Disturbs, distresses" , "Disturbs or knocks over" , "Reversals" .)