Chūnin Challenge: Rock Lee vs. Sasuke!

is episode 22 of the original Naruto anime.

Synopsis
Sasuke seems to have attracted the attention of Rock Lee, who challenges him to a fight. Rock Lee is not only interested in seeing how his skills match up against a descendant of the Uchiha clan, but he also has a mad crush on Sakura, much to her dismay. Feeling neglected in his teammates' shadows, Naruto offers to fight in Sasuke's place. Without wasting time, he charges, but is easily knocked out by Rock Lee. Rock Lee explains that they cannot beat him because he is the strongest of the Konoha Genin right now. Now interested, Sasuke accepts his challenge.

Sasuke attacks and is met by Leaf hurricane(Konoha Whirlwind) and gets knocked backwards. As he gets back up, he prepares to use his Sharingan moves to figure out Rock Lee's technique. He again charges Rock Lee, but again, Rock Lee is able to hit him. Rock Lee explains that his moves are neither ninja nor illusory - just straight hand to hand fighting. Unfortunately, with hand to hand fighting, Sasuke's Sharingan isn't helpful because even if he can see the techniques, his body can't move fast enough to react. Rock Lee does Shadow of the Dancing leaf to finish off Sasuke, but a large turtle stops his attack before it hits.

The turtle reprimands Rock Lee for using his forbidden technique. Guy then appears on top of the turtle and punches Rock Lee hard in the face as punishment. The two then cry and make up. As Kakashi's three ninjas stare at this ridiculous scene in complete shock, Gai asks how his eternal rival, Kakashi, is doing. He's ahead in the match record, which stands at 50 wins and 49 losses. Guy also says that he is much faster and stronger than Kakashi.

When Guy left, Rock Lee then confesses that he is not the strongest Genin - Neji Hyuga is. Naruto comments to Sasuke that Rock Lee must have been training until he dropped and that Lee trains harder than Sasuke. In the end Sasuke, Naruto and Sakura walk out of the building thinking about the chunin exams.