That would be episode 196.
Naruto Shippuden: Drive Towards Darkness
Air date: 01/27/2011
Sasuke’s jealousy of Naruto’s tremendous growth in strength causes friction between the two. Tsunade decides to give them some time apart by assigning them separate missions.
Mainly because Naruto transforms to Sasuke and he goes :" SASUKE KIIIIIIIIIICK! SASUKE PUNCHHHHH! SASUKE CHOP. CHOP. CHOP!"
naruto vs pain and soon naruto vs kyubi