Sasuke uses a replacment jutsu to appear behind Naruto, and uses his Kusanagi sword and chidori currentto paralyse him.
chidori current:
A variation on a regular Chidori developed by Sasuke Uchiha during his two-and-a-half year training with Orochimaru, this jutsu allows the user to generate electrically charged chakra from his body, instead of just concentrating it in his hand. The electricity can be channeled anywhere, allowing Sasuke to enhance his attacks or defend himself. As an offensive technique, because the electricity isn't focused, it doesn't kill on contact, only paralyzes. The Current can also be sent through the ground to attack opponents from their blind spot. Sasuke can also channel the electricity through his Kusanagi sword increasing its overall strength and cutting power, as well as making the area cut numb.