For all those people saying Sasuke can supress the Kyuubi's chakra, nullifying Naruto's most fearsome weapon, I don't think Sasuke could have supressed it if Naruto wasn't actively resisting it and keeping control of himself and his emotions.
If you go back to the chapter where Naruto first starts transforming in front of Orochimaru in their battle on the bridge, there is a scene where Orochimaru is looking into the eyes of Naruto. After that, he appears in front of the Kyuubi, similar to how Sasuke was.
However, unlike his encounter with Sasuke, Naruto had fully given in to his rage, and the Kiyubi managed to banish Orochimaru with just a mere roar, disintergrating Orochimaru's body in Naruto's inner dimension.
If anything, Sasuke probably learned the eye technique from Orochimaru and it would have failed if not for Naruto resisting the Kyuubi.