He easily defeated General Grievous, who has slaughtered countless Jedi and has gone toe to toe with the likes of Windu and Kenobi. Kit Fisto was regarded as the among the greatest lightsaber duelists not only in the Order, but in the Order's history.
Among all Sith Warriors challenging him, only Darth Malgus was able to defeat him. Ven Zallow blitzed two competent Sith Warriors, deflected firepower of Eleena Darru without even looking at her, overwhelmed Lord Adraas, and injured Darth Malgus.