Guan Yu fell for the ruse and withdrew the backup forces and advanced towards Fancheng. When Cao Cao heard of the attack at Fancheng, he sent Yu Jin to lead an army to relief Cao Ren, but Yu Jin lost the battle and surrendered to Guan Yu. Guan Yu's troops increased in numbers after his victory so he lacked food supplies. He sent his men to seize grain from one of Sun Quan's depots along the Xiang River. When Sun Quan heard about it, he sent Lü Meng ahead to invade Jing Province while he followed up behind. Lü Meng arrived at Xunyang County (尋陽縣; southwest of present-day Huangmei County, Hubei), where he ordered his elite soldiers to disguise themselves as merchants and sail towards Nan Commandery. On the journey, they captured the watchtowers set up by Guan Yu along the river to prevent the defenders from learning of their approach. Guan Yu was totally unaware of this. Shi Ren, who was defending Gong'an County, surrendered to Lü Meng after Yu Fan, an official under Sun Quan, persuaded him to do so. Earlier on, Guan Yu had punished Mi Fang for negligently causing some weapons to be destroyed in a fire. Although the incident was over, Mi Fang still feared Guan Yu. Lü Meng showed understanding towards Mi Fang and convinced him to surrender as well.