In reality the truth is that as with Beauty, Victory is in the eye of the beholder.
For example Lee at Gettysburg fought for three days. On the first two days the Union army was routed off the battlefields. Although the victory wasn't a total defeat for the Union. The third day was somewhat different as to the outcome. But the fourth day neither army was in a position or condition to attack the other. Lee withdrew on the fifth day. So who was the real victor? The Union army was not in a condition to pursue or to cut Lee of from his withdrawel even with a flooding Potomac river to cross.
Lee objective of carring the war to the North wasn't total complete but the Army of the Potomac didn't take up the offensive that summer or fall either.
Now had Lee on the first day of Gettysburg after defeating the 1st and 11th Corp NOT press Union retreat and developed his lines after the Union retreated to Cemetery Ridge. Had Lee withdrawen back down the Hagerstown Pike and consentrated his 2nd and 3rd Corp with Longstreets 1st Corp. Would Gettysburg have been considered a Union Victory or a Confederate Victory?
The Union Army would have still needed time to consentrate its scattered corps. And the 1st and 11th corp were not in shape to pursue. It is possible that Lee could have caught one, maybe two, other union corps in traps before the remained could come up to support them.