"Kunoichi Rumble: The Rivals Get Serious!" (ライバル激突!オトメ心は本気モード, Raibaru Gekitotsu! Otome Gokoro wa Honki Mōdo) is episode 41 of the original Naruto anime.
Kankurō easily wins his battle against Misumi by tricking him into attacking Karasu, Kankurō's puppet. In retaliation, Karasu snaps Misumi's neck, though he survives due to his ability to contort himself. The fourth match is between Sakura Haruno and Ino Yamanaka. The two begin fighting instantly, although they both fail to successfully attack the other. Neji wonders if their fighting skill is the best kunoichi can do, only for Tenten to state that their lack of fighting prowess is not because they are female, but rather because they are restraining themselves. Sakura, unwilling to lose to Ino and not happy with the fact that Ino is pulling her punches and taking pity on her, insults Ino.
A flashback is shown, where Sakura chooses to wear her forehead protector on her head instead of on her forehead, telling Ino that she'll only wear it on her forehead when she becomes a true shinobi. After trading insults, Sakura removes her forehead protector from her head and places it on her forehead; Ino removes hers from her waist and also places it on her forehead. As true rivals, the pair then rush at one another, finally deciding to take the battle seriously.
In a flashback, Sakura visits Ino in the woods to tell her that she was placed on Sasuke's team, and Ino reacts as if it is news to her; however, Ino was present in the classroom when Iruka Umino placed Sakura on Sasuke's team. However, it should be noted that Ino being present during the team formations is exclusive to the anime, as she was not present in the manga.