Despite heavy Confederate casualties (9,000), the Battle of Second Bull Run (known as Second Manassas in the South) was a decisive victory for the rebels, as Lee had managed a strategic offensive against an enemy force (Pope and McClellan’s) twice the size of his own.Click to see full answer. Also question is, what is the significance of the Battle of Bull Run?The First Battle of Bull Run (also known as the First Manassas) was fought on July 21, 1861. It was the first major battle of the Civil War and resulted in a Confederate victory.Additionally, when did the Second Battle of Bull Run take place? 1862 Correspondingly, what happened in the Second Battle of Bull Run? The Confederate victory drove the Union army from eastern Virginia and laid the groundwork for the Confederate invasion of Maryland. Bull Run, Second Battle of; Second ManassasSecond Battle of Bull Run. Confederate forces under Gen. Robert E. Lee defeated a Union army under the command of Maj.What was the result of the defeat of the Union forces at the Second Battle of Bull Run or Manassas?The Second Battle of Bull Run in Virginia was a tremendous victory for Robert E. Lee and the Confederate Army of Northern Virginia. Lee’s decision to strike before George McClellan’s Army of the Potomac could provide support to John Pope’s Army of Virginia resulted in a crushing defeat for the Union.