The Confederate plan was for Pillow to push McClernand out of the way and for Buckner to move his division across Wynn's Ferry Road and act as rear guard for the remainder of the army as it withdrew from Donelson and moved east. A lone regiment from Buckner's division—the 30th Tennessee—was designated to stay in the trenches and prevent Federal pursuit. The attack started well, and after two hours of heavy fighting, Pillow's men were able to push McClernand out of the way and open the escape route. It was in this attack that Union troops in the West first heard the famous, unnerving rebel yell.
The attack was primarily successful because of the poor positioning of McClernand's troops, and a flanking attack by sometimes-dismounted Confederate cavalry under Forrest. The brigades of Cols. Richard Oglesby and John McArthur were hit hardest; they withdrew in a generally orderly manner to the rear for regrouping and resupply. McClernand sent messengers to obtain assistance from Lew Wallace, but Wallace was reluctant to act without orders from Grant, who was still absent. McClernand's withdrawal had not yet assumed the frantic energy of a rout, but ammunition was running out. (The army of former quartermaster Ulysses S. Grant had not yet learned to organize supply lines effectively, and extra ammunition was not immediately available to these front-line brigades.) A second messenger arrived at Wallace's headquarters in tears, crying "Our right flank is turned! ... The whole army is in danger!" Wallace finally released one of his brigades, under Col. Charles Cruft, to aid McClernand. Cruft's brigade replaced Oglesby's and McArthur's in the line, but as they realized they were being flanked, they too began to fall back.
Despite seeing that his attack was successful and his escape route was open, by 1:30 p.m. Pillow believed he should regroup and resupply his wing before pushing forward and, to the amazement of Floyd and Buckner, he ordered his men back to their trenches. At that moment, Floyd lost his nerve and, believing that C.F. Smith's division was being heavily reinforced, ordered the entire force back inside the lines of Fort Donelson.