Zhang He
As Wang Ping predicted, Zhang He took advantage of Ma Su's mistake by striking at the Shu camp's water supply. Scattering Wang Ping's much smaller force, he succeeded in cutting off the enemy's water supply. The parched soldiers of Shu were easily defeated when Zhang He then launched an offensive on the main camp itself. Wang Ping with only a handful of soldiers did his best to keep the retreat organized and ordered his soldiers to beat their drums loudly to create the impression that reinforcements had arrived. Zhang He believed this to possibly be a sign of an ambush and so he did not pursue. When Zhuge Liang arrived, he attempted to defeat Zhang He however he didn't find a way to take a position and so the Shu army had to retreat to Hanzhong.