"Kakashi: Sharingan Warrior!" (写輪眼のカカシ, Sharingan no Kakashi) is episode 9 of the original Naruto anime.
Naruto's strategy and teamwork with Sasuke is a success, and Zabuza is forced to break his hold on Kakashi to avoid their attack. Saved from Zabuza's Water Prison Technique, Kakashi attacks his enemy with multiple water techniques copied from Zabuza using his Sharingan. Zabuza becomes agitated seeing his own techniques used against him, and Kakashi easily defeats him. Before Kakashi can deliver the finishing blow, Zabuza is seemingly killed by a young hunter-nin from Kirigakure. Naruto is angry and jealous that someone so young could easily defeat an opponent that gave Team 7 so much trouble, but Kakashi says that there are many ninja younger than Naruto yet stronger than himself. The hunter-nin leaves with Zabuza's body, and Kakashi collapses from exhaustion due to the overuse of his Sharingan.