MELBOURNE, Jan 30 (Reuters) - Novak Djokovic channelled his halcyon days in a five-set classic to dethrone Jannik Sinner and become the oldest man to reach the Australian Open final in the professional era at a rocking Rod Laver Arena.
Four months before his 39th birthday, Djokovic showed he remains unbeatable on his day as he sent the double defending champion packing with a 3-6 6-3 4-6 6-4 6-4 win completed in the early hours of Saturday morning.
"It feels surreal to be honest playing over four hours," Djokovic said on court.
"I was reminiscing in 2012 when I played Rafa (Nadal) in the final, that was six hours almost.
"The level of intensity and quality was high (against Sinner) and that was the only way to have a chance to win.
"He won the last five matches against me, he had my mobile number, so I had to change my number tonight.
"Jokes aside I said at the net: 'Thanks for allowing me at least one'. Tremendous respect, an incredible player. He pushed me to the limit, so he deserves applause for his performance."
Djokovic will meet world number one Carlos Alcaraz in Sunday's decider, the Spaniard having fought off Alexander Zverev in the longest Australian Open semi-final.
Eighteen years after his first Melbourne crown, Djokovic will strive for a record-extending 11th against Alcaraz and the unprecedented 25th Grand Slam title that has eluded him.
Djokovic needed incredible fortune to reach the semi-finals, with his quarter-final opponent Lorenzo Musetti retiring injured after taking the first two sets.
The Serb enjoyed a walkover in the fourth round as well, when Jakub Mensik pulled out.
But it was hard work and mental toughness that got Djokovic over the line against Sinner, a player who had beaten him in their previous five matches.
Victory came grudgingly.
He had to save a slew of break points in the decisive set before finally getting a look at Sinner's serve at 3-3.
Flooring the Italian in three punishing rallies, the Serb broke him to lead 4-3, raised one fist and threw an icy stare at his player's box.
Djokovic had to save another three break points in the next service game but sent Serbian fans into delirium when he survived them all and held with an ace.
Serving for the match at 5-4, Djokovic summoned the grit and champion spirit of 20 years at the top, setting up two match points with a forehand winner down the line.
Sinner saved both but finally fired a backhand wide to concede, leaving Djokovic to throw away his racket, get down on his knees and cross his chest in thanks to the tennis gods.
(Additional reporting by Shrivathsa Sridhar in Melbourne; Editing by Alison Williams and Toby Davis)
