How did Lincolns loss turn into a victory

Answer is explained below.

Explanation:

For preserving the Union and bringing an end to slavery, and for his unique character and powerful oratory, Lincoln is hailed as one of the greatest American presidents.

Despite having a low win chances, Lincoln won with a overwhelming majority of votes. He took every state, except few. He received around 55% of the popular vote and 212 electoral votes to McClellan's 21 votes. A huge part of the Union soldiers voted for Lincoln as well, demonstrating their readiness to keep combative and denial to accept defeat.