Gaara vs. Rock Lee: The Power of Youth Explodes!

is episode 48 of the original Naruto anime.

Synopsis
After a long wait, Rock Lee is set to fight against Gaara. At first it seems as though Lee's Strong Fist taijutsu would be ineffective because of Gaara's Shield of Sand, a wall of sand that automatically rises to protect Gaara regardless of his will. Lee soon reveals that he has been wearing heavy leg weights and removes them, allowing him to move faster than before and to ultimately bypass Gaara's sand. Lee attempts his Front Lotus.