Grant moved quickly to exploit the opening and told Smith, "All has failed on our right—you must take Fort Donelson." Smith replied, "I will do it." Smith formed his two remaining brigades to make an attack. Lauman's brigade would be the main attack, spearheaded by Col. James Tuttle's 2nd Iowa Infantry. Cook's brigade would be in support to the right and rear and act as a feint to draw fire away from Lauman's brigade. Smith's two-brigade attack quickly seized the outer line of entrenchments on the Confederate right from the 30th Tennessee, commanded by Col. John W. Head, who had been left behind from Buckner's division. Despite two hours of repeated counterattacks, the Confederates could not repel Smith from the captured earthworks. The Union was now poised to seize Fort Donelson and its river batteries when light returned the next morning.