The third seed was second best through two sets but won two tie-breaks before clinching a 5-7 3-6 7-6 (4) 7-6 (5) 6-3 victory after midnight on Rod Laver Arena.

It capped a dramatic day of tennis following Jannik Sinner's upset of Novak Djokovic in the other semi-final to guarantee a first-time champion at Melbourne Park.

Having lost to Djokovic in 2021 and Rafael Nadal from two sets up in 2022, Medvedev will hope this is finally his year.

"I was a little bit lost but during the third set I started saying that, if I lose this match, I want to be prod of myself, I want to fight for every point," he said. "I'm very proud.

"Physically and mentally it's tough five sets. Many times in the fifth I was not strong enough. One month ago I wanted to change a little bit to try to be even more strong mentally. I'm still yet far from being perfect but I'm trying."

The Russian, who will contest a sixth slam final, trailed Emil Ruusuvuori by two sets in the second round in a contest that finished at 3.39am, and also needed five sets to defeat Hubert Hurkacz in a gruelling quarter-final.

Zverev came through two five-set matches in his first four rounds, winning deciding tie-breaks against Lukas Klein and Cameron Norrie, but stepped up a gear to knock out Carlos Alcaraz in the quarter-finals and continued in the same vein here.

Five double faults from Medvedev contributed to two breaks of serve in his opening three games but Zverev was unable to capitalise on his lead, Medvedev breaking the sixth seed when he served for the set as the rallies became longer and longer.

Zverev broke again in the 11th game and this time managed to make it across the line, with one 51-shot rally leaving both men gasping for air.

There is no love lost between them, with things reaching a head in Monte Carlo last year, when Zverev branded his opponent œone of the most unfair players in the world following a tense clash.

That was one of six matches they contested in 2023, with Medvedev winning five of them.

Things remained civil here, but Medvedev's frustration grew in the second set as Zverev really began to take control from the back of the court, breaking serve twice more.

The Russian pushed hard for a foothold in the match in the third set, moving closer to the baseline and exerting some pressure, but Zverev held firm until the tie-break.

Winning that gave Medvedev the belief he could recover, but he was unable to find a chink in Zverev's armour through the fourth set.

A double fault from Medvedev at 4-4 in the tie-break gave Zverev two serves for it but instead both points went to the Russian, the second a very fortunate return winner that scraped over the net, and an ace sent the contest to a fifth set.

Zverev's annoyance boiled over when a wild volley gave Medvedev two break points at 2-2, the sixth seed smacking the top of the net twice with his racket and earning a warning for unsportsmanlike conduct.

He saved both but a third followed and this time he netted a forehand to give Medvedev his first break of serve since the opening set.

There were four hours and 17 minutes on the clock when a Zverev backhand over the baseline gave Medvedev his first match point, and moments later he was able to celebrate another remarkable win.

Fall of Wickets	Player	Score	Overs	Bowler	Out
6	Abdul Majid	82	15.2	Karma Dorji	Clean Bowled
5	Sohail Ahmed	81	14.5	Namgay Thinley	Catch OUT
4	Yasser Nazir	54	9.1	Tashi Dorji	LBW
3	Asif Ali	47	7.3		Run OUT
2	Fiaz Ahmed	46	6.5	Tashi Phuntsho	Catch OUT
1	Prashant Kurup	20	2.4	Tashi Phuntsho	Catch OUT

Finished Quadrangular Twenty20 Series (Thailand)