"Showdown: Gaara vs. Kimimaro" (最強対決!我愛羅VS君麻呂!!, Saikyō Taiketsu! Gaara tai Kimimaro!!) is episode 126 of the original Naruto anime.
Gaara arrives just in time to save Lee's life. He mentions that Lee isn't as fast or agile as he was before, and remembers the injuries he inflicted on Lee during the Chūnin Exams. Not wanting Lee to get hurt, Gaara uses his sand to pull Lee back and tells him to sit the fight out. Gaara uses his sand to fight Kimimaro, which prompts Kimimaro to attempt to destroy Gaara's gourd, as he believes it is the only source of sand Gaara possesses. Gaara, however, uses the sand on the ground to restrain Kimimaro and then uses his Sand Drizzle technique followed with a Sand Binding Coffin, although Kimimaro avoids being crushed to death due to his bone density. Gaara decides to use his Sand Waterfall Funeral to attempt to crush Kimimaro again, though by activating his cursed seal, Kimimaro survives the attack. Calling upon a greater amount of Sand, Gaara uses his Quicksand Waterfall Flow to create a sand tsunami and then uses his Sand Waterfall Imperial Funeral technique that not only smothers Kimimaro, but levels the terrain as well. To both Gaara and Kimimaro's surprise, the latter survives the attack.
Gaara mentions to Lee that Kimimaro's eyes remind him of Sasuke's, claiming that their eyes belie the fact that both wish to find the purpose of their existence. Stuck within the sand, Kimimaro reminisces on how he was raised in the darkness, imprisoned in a cell because of his kekkei genkai, only being let out to fight. The clan's patriarch used him as a weapon in an attempt to take down Kirigakure. Kimimaro was tasked with the sole objective of killing any ninja from Kirigakure, and encountered Orochimaru, Zabuza and Haku, the latter two telling Kimimaro that they were not from Kiri in order to avoid a fight. After killing all of those in his way, Kimimaro discovered that the entire Kaguya Clan has been slaughtered as well. Feeling lonely and without a purpose, Kimimaro wandered on his own until he was found by Orochimaru, who took him in. Kimimaro believes that his sole purpose in life is to protect Orochimaru and his goals, hence why he hasn't died yet. Going into the second state of his cursed seal, Kimimaro breaks free of the sand and lunges towards Gaara and Lee.