After a surprise attack by the Confederates, General Grant was able to pull off a win at this battle, though it cost him over 13,000 soldiers

The question refers to the Battle of Shiloh.

Explanation:

The Battle of Shiloh was a major Civil War battle that took place on April 6 and April 7, 1862 in southwestern Tennessee. Confederate forces under the command of General Albert Johnston suddenly attacked the positions of the US Army, led by Major General Ulysses Grant, and were very close to the complete defeat of the northerners.

On the first day of the battle, the Mississippi Army struck with the goal of pushing the federal army away from the Tennessee River and driving it into swamps on the west bank. The reckoning was to smash Grant's army before it combined with General Buell's army. During a fierce attack, the military formations of the southerners' army were upset, which allowed Grant to withdraw his troops not to the west of the river, where the Confederates planned to push them, but to the northeast, to the town of Pittsburgh-Landing. The offensive of the southerners continued, but the remains of the division of Brigadier General Prentiss were able to defend themselves and, under cover of artillery, repelled 12 attacks, which allowed Grant to gain time and put the battle lines in order.

During one of the attacks, General Johnston personally led the attack, but was seriously wounded in the thigh and soon died of blood loss. General Beauregard, who assumed the general command, decided not to continue to attack the positions of the northerners and postponed the decisive assault on the morning of April 7th.

However, the southerners were too hasty to conclude that they won: General Buell's army joined Grant at night and in the morning the balance of power on the battlefield became completely different. Federal troops launched a counterattack on the entire battle front and the southerners were forced to retreat. By that time, it was the bloodiest battle in US history. As a result of the defeat, the Confederates missed the last opportunity to block the advance of federal forces to the Mississippi.