李愬
Li Su thereafter targeted Li You and, after setting a trap for Li You with 300 cavalry soldiers while engaging him, Li Su's officer Shi Yongcheng () was in fact able to capture Li You. Li Su's soldiers, resentful at how many casualties Li You had inflicted on them, demanded that Li You be put to death, but Li Su resisted the call and treated Li You with respect, causing Li You to be touched. It was said that when discussing tactics about how to capture Cai Prefecture, Li Su would discuss only with Li You and a fellow Zhangyi captive officer, Li Zhongyi (). The other officers feared that Li You would, at least meetings turn against Li Su and assassinate him, but Li Su did not heed their warnings. Thereafter, there were reports to Emperor Xianzong by those jealous of Li You that Li You must have been plotting still with the Zhangyi rebels, and there were renewed calls for Li You's execution. Li Su, after holding Li You and weeping, publicly declared that he would send Li You to Emperor Xianzong for Emperor Xianzong to execute him — but sent a secret petition to Emperor Xianzong, stating that if Li You were executed, the campaign would fail. Emperor Xianzong, after reviewing the petition, released Li You and returned him to Li Su. Li Su subsequently made Li You his guard commander