 Subsequently, before he and the other generals could reach Chang'an, Pugu died, and the Huige and Tufan army, while initially still advancing toward Chang'an, slowed down.He participated in the subsequent defense of Chang'an, although Huige forces withdrew after Guo persuaded them to do so, and Tufan forces withdrew thereafter as well.In 767, as the military governor of Tonghua Circuit (同華, in modern Weinan, Shaanxi), Zhou Zhiguang (), became increasingly violent (including, among other things, slaughtering the entire household of fellow military governor Du Mian () and threatening to the emperor, Emperor Daizong sent Guo to attack Zhou, whose subordinates subsequently killed him and surrendered.