The Reason He was Late…!! (遅刻の理由…!!, Chikoku no Riyū…!!) is chapter 113 of the Naruto manga.
Sealed within his Shield of Sand, Gaara prepares for how he will kill Sasuke. Still unable to pierce it, Sasuke falls back to prepare his own attack. Naruto pleads with Kakashi to stop the match, but Kakashi merely tells him to watch. Sasuke readies the Chidori, Kakashi's signature technique that he spent that last month teaching to Sasuke. Combining the Chidori's piercing potential with the speed mimicked from Lee, Sasuke charges at Gaara and breaks through the sphere, surprising all observers.