winner vs upsetter

winner and upsetter both are nouns.

Word	Noun	Adjective	Verb	Adverb
winner	Yes	No	No	No
upsetter	Yes	No	No	No

As nouns, upsetter is a hyponym of winner; that is, upsetter is a word with a more specific, narrower meaning than winner:

Other hyponyms of winner include contestee, medalist, medallist, walloper.

winner (noun)	upsetter (noun)
the contestant who wins the contest	an unexpected winner; someone who defeats the favorite competitor
a gambler who wins a bet
a person with a record of successes