In 219, when Guan Yu was being surrounded by Sun Quan's forces in Maicheng (), Liu Feng refused to provide reinforcements partly because Meng Da reminded Liu Feng of Guan Yu's disapproval. When the general Liao Hua told Liu Bei that Guan Yu died because Liu Feng and Meng Da did not send reinforcements, Liu Bei began to resent the two and even plotted their arrest. Meng Da became afraid and defected to the state of Cao Wei and sent Liu Feng a message, urging him to defect as well. In anger, Liu Feng executed the messenger and went to battle Meng Da, who was now aided by the Wei generals Xu Huang and Xiahou Shang. As Liu Feng was out of the city, the defender Shen Dan surrendered to Wei and shot arrows at Liu Feng's men. Defeated, Liu Feng returned to Chengdu with only slightly more than a hundred horsemen.
