As the battle progresses, Sasuke begins to adapt to Haku's blinding speed. He uses his Fire Release: Great Fireball Technique to retaliate, and for the first time, he starts to perceive Haku's movements with his developing eyes.
Kakashi warns Sakura that while Naruto and Sasuke have the heart of a ninja, they lack the "instinct to kill," which is why they are struggling against a cold-blooded assassin like Haku. Characters Featured Stai guardando Naruto Ep 15 ITA
Facing a psychological and tactical stalemate against Zabuza. As the battle progresses, Sasuke begins to adapt