Darth Traya wins. Revan's biggest advantage in this battle is the Republic fleet. But just like we saw with the Harbinger, Sith Assassins can neutralize that advantage with ease. This forces Revan to mobilize troops for an attack on Malachor V, where they would be utterly crushed. Whether the Jedi there are killed by the Sith or turned by Malachor's dark energies, Revan would lose. And then, Traya turns Revan to the Dark Side.
Traya wins a sound victory.
If Revan turned Dark, again. would not he just get stronger? PLUS, Revan would still be alive. The match would not be over.