Four breaks of serve were exchanged throughout a bizarre second set, which could have very much been Nadal's.
The Spaniard was brilliant in saving four set points off Dimitrov, only to falter on his own serve and gift him the second set 7-5.
Momentum swung between both men and tensions even boiled over at times.
Nadal had a terse exchange with the chair umpire midway through the third set, believed to be about the time violation penalty he was hit with in the second set.
The third set was a tight affair, surprisingly with no breaks of serve in it, after the chaos of the second. It would go to a tie-break, Nadal simply outworked his younger challenger, taking it 7-5 to go two sets ahead.
The fourth set would be much the same, and would again go to a tie-break. It was there though that Dimitrov's aggressive game would pay dividends.
Dimitrov jumped all over the Nadal serve in the tie-break, taking it 7-4 to send the match into a decider.
The Bulgarian took all the momentum into the fifth set and after needing over 10 minutes to hold serve in the first game, the twists would continue.
As the game surged beyond the four-hour mark, the quality somehow increased. The first two games of the fifth set contained 26 points. The fatigue levels rose, and so did the average rally length.
When looking for a pivotal moment in this match - head straight to the eighth game of the fifth set. Down 4-3 in the final set, Nadal saved two break points to hold serve in a miraculous show of grit.
Failure would have seen Dimitrov serve for the match, but Nadal had other ideas.
The Spaniard used the momentum to turn the pressure back on the 15th seed Bulgarian and soon enough it would tell.
Dimitrov would double fault, handing Nadal an opportunity at 0-30.
Nadal would soon have a breakpoint and he'd only need one of them, moving to 5-4 and serving for the match.
After his serve deserted him at times throughout the epic encounter, Nadal will now meet Federer in Sunday night's final, resuming a rivalry that has gripped the sport over the last decade.
The showdown was unlikely just months ago, when both men faced a return from injury.
Nadal now shifts focus to Sunday night, as he has less than 48 hours to prepare. The Spaniard saying post-match that he's honoured to share the stage again with his great rival.
"You know, for me, it's a privilege and very special thing I think for both of us to be in the final again," Nadal said.
"It's amazing to have another chance to compete against each other after a couple of years having some problems."
