At noon, Union troops advanced with a cheer. Blair's brigade moved on the left, DeCourcy's in the center, followed by Brig. Gen. John M. Thayer's brigade on the right; Thayer's brigade lost its way and only one regiment, the 4th Iowa Infantry, was engaged. Colonel James A. Williamson, commanding the 4th Iowa, was later awarded the Medal of Honor for his actions that day. They crossed water barriers and abatis and carried the advance rifle pits on the weight of sheer numbers, but met stiff resistance when they came against the main Confederate line and began to crumble under the heavy fire. The survivors fell back across the bayou on a corduroy bridge. S.D. Lee ordered his men to make a counterattack, during which they captured 332 Union soldiers and four battle flags.