Nadal was almost forced out of the event before it had even started after hurting his knee when sitting on a chair at his hotel but now stands on the brink of an 11th grand slam crown.
His win over Federer was a victory for persistence and sheer bloody-mindedness.
Having been overwhelmed early on he gradually worked his way back into a contest which developed into another classic between two of the game's greatest ever players to finally prevail 6-7 (5/7) 6-3 7-6 (7/5) 6-4.
"On the Sunday afternoon, 24 hours before I was due to play my first match, I was in the room crying because I believed I didn't have the chance to play in Melbourne," said Nadal, who will meet either Andy Murray or Novak Djokovic in Sunday's final.
"It was a very, very tough situation for me in those hours.
"And two weeks later I am here in the final. It is a dream for me.
"I have been in the last four grand slam finals now which is a great effort."