In 773, during a Tufan incursion, Ma suffered a battle loss at the hands of Tufan forces and was trapped outside the city, unable to enter. His subordinate Jiao Lingchen () fled back into the city and suggested that Duan close the city gates to get ready for the Tufan assault. Duan responded, "The Governor has not returned. We need to use all of our strength to fight the barbarians. How can we just seek to spare ourselves?" He then told Jiao, "According to military laws, the penalty for losing your commander is death. Have you forgotten that?" Jiao became fearful, and Duan sent him back out to fight Tufan forces, forcing them to withdraw and allowing Ma to return to the city.