ACKSHUALLY
Gil-galad and Elendil were the ones that defeated Sauron when the ring was taken from him. Contrary to how the movies portrayed it, Isildur did not cut the ring from Sauron's hand as an act of desperation in a lost battle, he cut the ring from Sauron's broken body after he had been beaten on the field of battle. Elendil was a pure-blooded Numenorean but it's doubtful that he really contributed much to the fight considering that Gil-galad was an immensely powerful elf of the First Age. Heroic elves of the First Age were easily on par with the Maiar, Glorfindel killed a Balrog during the sack of Gondolin and during the events of Fellowship the Nazgul fled at his mere presence. Gothmog, the greatest of the Balrogs, was slain in a duel with Ecthelion of the Fountain, also during the sack of Gondolin. For another reference for the relative power of a Balrog, seven Balrogs were able to make Ungoliant flee after she attacked Morgoth. So a group of Maiar were able to chase off a creature on par with one of the Greater Ainur, and were intent on hunting her down to kill her if Morgoth hadn't reined them in.
As for Sauron's eventual death at the end of the Third Age, it was more his own greed for power that killed him rather than the actions of Frodo or Gollum. In binding himself to the One Ring he may have radically increased his power, but he also created the mortal weakness that ultimately killed him.
