It will be the ninth time that Nadal and Federer will play for a Grand Slam title, with Nadal winning six of the previous eight finals meetings. They have not met for a major championship since the 2011 French Open, when Nadal won his sixth of nine titles at Roland Garros.
The ninth-seeded Nadal fought off two break points in the eighth game of the fifth set before hitting a backhand winner down the line to break No. 15 Dimitrov in the next game and take a 5-4 lead. Nadal closed out the victory in the following game on his third match point to win in 4 hours, 56 minutes.
"Grigor was playing unbelievable. It was a great match. I feel very happy to be part of it. I enjoyed it a lot," Nadal said. "To qualify for the final in a match like this means a lot to me."
Ultimately, Dimitrov, determined as he was, came to the same semifinal end as Stan Wawrinka, Coco Vandeweghe and Mirjana Lucic-Baroni. On Friday, he couldn't stop an older, wiser, more relentless former No. 1 player.
It wasn't for a lack of trying in this rousing and riotous match.
Dimitrov came into the semifinals against Nadal as the hottest player in tennis, sporting a new attitude and a sparkling 10-0 record in 2017. The 25-year-old Bulgarian fought hard, and when it was finally over, Nadal fell facedown onto the court at Rod Laver Arena and replayed some of the most difficult times in his head.
"I worked a lot this month and a half at home," Nadal said, his voice thick with emotion in the on-court interview. "I never, ever dreamed to be back in the final of the second tournament of the year.
"Here I am. I feel lucky."
He's not the only one.
That's because the marquee, back-to-the-future final wished for by multitudes of tennis fans has come to pass. Nadal will take on Federer at Rod Laver Arena on Sunday in a match that will have a huge impact on the race for Grand Slam singles titles.
Federer is the all-time men's leader, with 17, while Nadal is tied for second with retired Pete Sampras at 14.
"For me is a very, very special thing and for both of us to be in the final of a major," Nadal said, "after a couple of years of having some problems."
And so, we have a pair of unimaginable blockbuster finals: Federer vs. Nadal and Serena vs.? Venus Williams. With a combined 60 Grand Slam singles titles, these are the two most decorated active players on the men's and women's sides.
Even so, these weren't the finals pairings many would have expected.?According to the pre-tournament odds from online bookmaker William Hill, the prospect of Federer-Nadal and Williams-Williams finals was 5,000-1.
Nadal, the 2009 Australian Open champion, is into his first Grand Slam final since 2014 at Roland Garros and his 21st overall. He is looking to become the first man to win each of the four Grand Slams twice.
He improved his record in Grand Slam semifinals to an impressive 21-3 and advanced to his fourth Australian Open final. He takes a 23-11 head-to-head record into his match with Federer, who hasn't beaten Nadal in a major final since Wimbledon in 2007.
"Is special play with Roger again in a final of a Grand Slam," Nadal said. "I cannot lie. Is great. Is exciting for me and for both of us that we still there and we still fighting for important events. So that's important for us, I think. That's very special. After that, you know, is a final. Is a very important match for both of us.
"I hope to be ready to compete well again. I need to go back to the hotel, to rest well and to recover from now."
Neither player was expected to get to the celebrated seventh match in Melbourne. Federer, seeded No. 17, missed six months with a knee injury in 2016, while Nadal had struggled with a wrist injury.
Federer, at 35, is the oldest male major finalist in 43 years. He will be helped by the fact that Nadal, 30, will get one fewer day to recover from this nearly five-hour match that ended at 12:45 a.m. local time. Federer beat Wawrinka in a five-setter Thursday night.
This is the first time since 1997 that the two Grand Slam finalists each had to weather two five-set matches in one tournament.
Friday featured a match of superb quality -- and it seemed to get better the longer it went. Against Dimitrov, Nadal was sometimes stretched to his limit, particularly when his fluky forehand missed.
It was, for the record, the second-longest match at this Australian Open. Dimitrov might have played the best match of his life, but he lost to a courageous warrior, the guy you'd want playing a five-hour, five-set match more than any other. The Bulgarian is, tellingly, 0-7 in matches lasting longer than 3? hours.
Nadal was broken at 5-6 in the second set when he sprayed a backhand long. It came on the fifth set-point opportunity for Dimitrov and broke a remarkable streak of 10 consecutive saved set points by Nadal.
The pivotal moments of the third-set tiebreaker proved the difference.
Nadal was relentless, defending well, pressing Dimitrov from the beginning and emerging with his third career tiebreak victory in three tries against the Bulgarian.
Dimitrov broke through in the fourth-set tiebreaker, playing with controlled aggression, and the match was level after almost four hours.
In the fifth set, down 3-4, Nadal fought off two break points. At 4-4, he broke Dimitrov's serve by chasing down a short ball and drilling a backhand winner down the line.
Serving it out was difficult. Nadal converted his third match point when one last Dimitrov backhand sailed long.
Dimitrov, who had been aiming to reach his first Grand Slam final, has been beaten by Nadal in eight of their nine matches.
After all of Nadal's travails in the past several years, the injuries and poor play that have consistently taken him out of contention in the majors, this one had to feel terrific.
Now, can he pull off a daunting turnaround?
"First of all," Nadal said in response to the first question about Federer, "I hope to recover well."
Nadal also talked about how hard it was to withdraw from a third-round match last year at Roland Garros -- saying he cried in the courtesy car on the way home -- and the difficulty of fighting back to the level of a Grand Slam finalist.
And he told the same poignant story Federer offered the night before: about Federer's gracious visit to Nadal's new tennis academy in Mallorca in the fall.
"We were supposed to play an exhibition match," Nadal said, "but he was injured with his knee and me with my wrist. We hit some balls with the juniors.
"Both of us never felt we're going to be here in the final of the Australian Open."
The Associated Press contributed to this report.