Mats says the key to Nadal's success was the way he managed to relax in the final set, which he won 9-7, and was able to hit his way out of trouble.
Nadal began to hit the ball harder and find the corners - a trait normally associated with Djokovic when he is under pressure.
The Serb was so close to inflicting Nadal's second ever defeat at Roland Garros - which was impressive in its own right given all the conditions suited the Spaniard.
But he was guilty of a few key errors in the fifth set, as Mats outlines in the video below.
Mats also turned his eye to the other semi-final in the mens' draw, with David Ferrer seeing off Jo-Wilfried Tsonga to reach his first Grand Slam final.