The Battle of Zava was fought on July 18, 1342 between the armies of the Sarbadars and the Kartids (or Kurt dynasty). Since their appearance as a political force in Khorasan, the Sarbadars had fought to expand their influence in north-eastern Iran and defend against the forces of the claiming IlkhanTogha Temür who sought to regain Khorasan. Mu'izz al-Din Husain, the chief of the Kartids of Herat, recognized Togha Temur's overlordship, and when the Sarbadars secured their hold on Khorasan they sought to eliminate the Kartid threat to the east.
The Sarbadars attacked the Kartids' territory in 1342, meeting the Kartid army in Zava (today called Torbat-e Heydarieh) on July 18, 1342. The battle started well for the Sarbadars, but when Hasan Juri was captured and killed, his supporters believed that he had been assassinated by Mas'ud's men and retreated. The retreat of Hasan's followers turned the battle in the Kartids' favor and the Sarbadars had to retreat back to Khorasan. Following the return home, Mas'ud attempted to rule without the support of the dervishes, but his power was decreased.