Anticipating an Ottoman invasion encouraged by the young and inexperienced new Ottoman sultan, Hungary co-operated with Venice and Pope Eugene IV to organize a new crusader army led by Hunyadi and Władysław III. On receipt of this news, Mehmet II understood that he was too young and inexperienced to successfully fight the coalition. He recalled Murad II to the throne to lead the army into battle, but Murad II refused. Angry at his father, who had long since retired to a contemplative life in southwestern Anatolia, Mehmed II wrote, "If you are the Sultan, come and lead your armies. If I am the Sultan I hereby order you to come and lead my armies." It was only after receiving this letter that Murad II agreed to lead the Ottoman army.

During the battle, the young king, ignoring Hunyadi's advice, rushed 500 of his Polish knights against the Ottoman center. They attempted to overrun the Janissary infantry and take Murad prisoner, and almost succeeded, but in front of Murad's tent Władysław's horse either fell into a trap or was stabbed, and the king was slain by mercenary Kodja Hazar, who beheaded him while doing so. The remaining coalition cavalry were demoralized and defeated by the Ottomans. Hunyadi narrowly escaped from the battlefield, but was captured and imprisoned by Wallachian soldiers. However, Vlad Dracul set him free before long.