Revan versus Kyp Durron
Revan
Versus
Kyp Durron
Who wins?
I say Revan
Revan
To Bane it seemed the teachings contained within the single Holocron surpassed those of the Academy's entire archives. Revan had discovered many of the rituals of the ancient Sith, and as the holocron's avatar explained their nature and purpose, Bane could barely wrap his mind around their awesome potential. Some of the rituals were so terrible-so dangerous to attempt, even for a true Sith Master-that he doubted he would ever dare to use them. (PoD)
As we see from PoD, Bane describes some of the darkside techniques Revan knew as possessing awesome potential. He mentions that the force storm he used on Russan was a technique he learned from Revan. As was the thought bomb.
Revan dueled Malak while Malak was empowered by the Star Forge. The Star Forge gave Malak a substantial boost in force powers, (the said Sith Lord was already known to possess knowledge on Sith Magics, and was a very powerful duelist and force uses). What more, Revan defeated Malak twice. Malak also stated that Revan's powers in the ligthside were far more superior than his already formidable abilities in the darkside.
Using a mysterious power source as yet undiscovered (complete Star Wars: Knights of the Old Republic to learn more), Darth Malak possesses extraordinary dark side Force powers (DE Sourcebook add on)
Revan was also a master of Echani precognition, an ability that in conjuction with his Jedi precognition gives him an advantage in dueling against Kyp Durron.
Kyp
While Durron may have manipulated a black hole, that is the only ability that impressed me. However this does not even translate into a dueling arena situation. Also Durron may have guided a lightning bolt into an ancient Sith Worm, but I would rank this below a full fledged force storm (as described by PoD, KOTOR.)
So in conclusion, I would state that Revan succeeds.