Kakashi: Sharingan Warrior!

is episode 9 of the original Naruto anime.

Synopsis
After Kakashi is saved, he attacks Zabuza with multiple water techniques. He also seems to copy and look into the future with his Sharingan and uses the many water jutsu that Zabuza knows. Kakashi's water jutsu eventually throw Zabuza into a tree and prepares to kill him, but is "murdered" by a hunter nin from the Hidden Mist Village.

Secretly, the hunter nin is an apprentice of Zabuza and faked his death.

With his teamwork with Sasuke, we see Naruto's strategy unfold and Zabuza is tricked into breaking his hold on Kakashi to avoid certain death.