What are Sauron's strengths/abilities?
From what I can understand he's great at manipulating people and getting them to do things for him and he's quite powerful as he can wipe out entire batallions at once. But Frieza destroys planets for jokes, I really don't see how Sauron can win this. Frieza also has telekinetic powers so magic probably wouldn't be so effective against him and he's pretty damn fast, a lot faster than Sauron probably is.
Ring wearing Sauron is a tough customer, he may lack some flashy phyiscal atributes and beam spam, yet he is quite unkillable while holding the ring, and he only got hurt when a Numenorean Enchanted Weapon (Andruil or Narsil) hitted him. Technically he is a minor god in LOTR mythology, and thanks to that he is really difficult to kill. In the movies they killed becouse he was separated from the ring, that was the source of his powers, like the phylactery for a Lich, but with the ring on, and without magical sword to cut him Frieza could destroy the planet, yet Sauron would remain untouched. He haves the power to alter reality in small yet significative matters and is master manipulator that could easily trick Kira or Lelouch with his silver tongue. He could offer more power to Frieza and corrupt him. Sauron could wipe batallions in the Silmarillion, and that were Batallions of uber-elfs, that would make look Legolas look silly while shooting arrows. He had the potential to destroy the world, yet he wanted to conquer it.
Frieza wont win because Sauron is unkillable unless you remove the ring and throw it to the flames of Mount Doom, thus having a fight in Netherrealm will only benefit Sauron, as he even without his ring, would be unkillable.
@Falken: He might be immortal but that doesn't mean he still can't be knocked out. One unrestrained energy-enhanced strike from Frieza would knock him out cold. Frieza could just spam planet-busting attacks, and even if they won't kill him, he'll still be knocked unconscious. Anyway, Frieza can still BFR him being that he is much faster, stronger and can fly.
@Falken: Can the ring prevent Sauron from having every single particle that makes him erased by an energy blast? I mean Frieza can just erase his Sauron's entire body with a powerful enough blast. Many immortal characters have been defeated that way. There would be nothing left of him anyway. Anyway, Sauron can't hurt Frieza anyway so it's a stalemate.
@Newdeath: To destroy completly banish Sauron you need to destroy not only the ring, you need to destroy Middle Earth and kill Eru Illuvatar, the God from Tolkien Mythology, Eru is omnipotent, and everything is part of his chant, even the ones that were banished such as Morgoth, since he wasnt destroyed, only exiled, and that was Sauron fate at LOTR end
So it's a tie
@othus12: Yes but that human was part of a uber-race of humans, the inhabitants of Numenor (LOTR Atlantis, Ancestors of Aragorn), and the sword was Mother of Magic Swords....
And as I explained, even separating the ring wont kill him, you need to destroy were it was forged, and unless Frieza can jump dimensions to Middle Earth and throw the ring to Mount Doom, Sauron will turn insubstancial, and possibly try to mind-rape Frieza
@Falken: You're actually arguing for Sauron? You are either fanw***ing or trolling, one or the other. The likes of saibamen would make your little "uber-race of humans" look like trash. LOTR has absolutely nothing on DBZ in terms of power (without including Eru anyway).
Frieza would utterly erase both Sauron and his ring, his level of power is simply that far above anything that Sauron has ever achieved. The ring would be powerless in the face of Frieza. The ring had absolutely no effect on Bombadil, for instance. Why? Because he was simply that powerful. To him it was just a trinket.
And your argument of "he'd have to kill Eru" is a bit ridiculous, that would be to erase his spirit. Generally it would be accepted as Sauron being destroyed if Freiza erased all earthly forms of him (so destroying him and the ring). Freiza stomps this, the whole of middle-earth would be powerless to stop someone of Freiza's level.
Without the ring he turns insustancial, so he wont get killed, and the Ring cannot be destroyed by any means Frieza haves (They Are Fighting on the Nether Realm of MK, so Mount Doom is no an option). Tom Bombadil is a mystery, we cant start to talk about him because we'll get into a war neither of us can win, there are a dozen of theories and we wont start analyzing them since it's offtopic. (The most accepted theory is that he is a Maiar tha just dont cares about anything and lacks any dark side to be lured towards, so the Ring, that can slowly turn anybody with a speck of evil into a monster)
Is a Tie because the intro states fight to the Death, and if they arent in Middle Earth, Frieza cannot destroy the ring, planet busting and everything. The Ring can only be destroyed in Mount Doom, so is a Tie, no fighter can kill the opponent...