The conversation between human and AI assistant.
Did there exist anyone besides Morgoth on Middle Earth that could defeat Sauron in a fair one on one fight?
What about the Valar and Maiar?
The Valar and Maiar were certainly immensely powerful, but they generally did not engage in physical combat with mortal beings unless it was absolutely necessary. It is possible that one of the Valar or Maiar could have defeated Sauron in a one on one fight, but it is difficult to say for certain.