The Spaniard has stormed back from injury and the brink of retirement to make the final in Melbourne, but faces stiff competition against the world number two and reigning US Open champion.
Prior to the start of this year's tournament, many would have been expecting it to be nine-time champion Novak Djokovic gunning for Grand Slam title number 21 in the final, but his much-publicised expulsion has opened the door for Nadal to edge ahead in that fascinating battle at the top of the all-time list.
Currently level with his great contemporary rivals Roger Federer and Djokovic on 20, Nadal has the chance to move out on his own on Sunday, and it is a chance he may not have been expecting.
The Spaniard has openly admitted that he considered retirement during his battles with injury last year and played down expectations heading into this tournament, yet he has once again battled through to a 29th Grand Slam final.
Just one of his 20 previous triumphs has come at the Australian Open, though, and that was all the way back in 2009; since then, he has reached the final four times but lost each one.
It has not been an entirely straightforward route to this year's showpiece either, most notably needing five sets to get past Denis Shapovalov in a gruelling semi-final.
Nonetheless, the 35-year-old recovered sufficiently to outclass Matteo Berrettini 6-3 6-2 3-6 6-3 in the semi-finals on Friday, but he will know that Sunday's contest will be an even tougher affair.
Medvedev himself was taken the distance in the quarter-finals - battling back from two sets down and saving a match point in a five-hour marathon against Felix Auger-Aliassime - and also needed four sets in the semi-final as he overcame rival Stefanos Tsitsipas 7-6 4-6 6-4 6-1.
That was his third four-setter at this year's tournament, but stamina should be on his side regardless with a 10-year advantage on Sunday's opponent.
Momentum may also be on his side as he carries on his good form from 2021; while Nadal was contemplating his future last year, Medvedev began to start fulfilling his potential and ended the year with his maiden Grand Slam crown.
No player other than Federer, Nadal and Djokovic has won back-to-back Grand Slam men's titles this century - Andre Agassi was the last with his US Open title in 1999 being followed by the Australian Open crown in 2000 - so victory for Medvedev would cement his place at the forefront of the next generation taking over from the 'big three'.
The Russian also reached the final in Melbourne last year, when he was beaten by Djokovic, but with one Grand Slam title now under his belt he will approach this year's showpiece with much more confidence.
Route to final
Semi-final: 6-3 6-2 3-6 6-3 vs. Matteo Berrettini
Quarter-final: 6-3 6-4 4-6 3-6 6-3 vs. Denis Shapovalov
Fourth round: 7-6 6-2 6-2 vs. Adrian Mannarino
Third round: 6-3 6-2 3-6 6-1 vs. Karen Khachanov
Second round: 6-2 6-3 6-4 vs. Yannick Hanfmann
First round: 6-1 6-4 6-2 vs. Marcos Giron
Semi-final: 7-6 4-6 6-4 6-1 vs. Stefanos Tsitsipas
Quarter-final: 6-7 3-6 7-6 7-5 6-4 vs. Felix Auger-Aliassime
Fourth round: 6-2 7-6 6-7 7-5 vs. Maxime Cressy
Third round: 6-4 6-4 6-2 vs. Botic van de Zandschulp
Second round: 7-6 6-4 4-6 6-2 vs. Nick Kyrgios
First round: 6-1 6-4 7-6 vs. Henri Laaksonen
Head To Head
Sunday's meeting will be just the fifth time these two have faced off, and it is Nadal who leads the head-to-head record 3-1 after the previous four.
However, Medvedev did win the most recent showdown between the pair, overcoming Nadal in the semi-finals of the ATP Finals in 2020.
All of their previous four matches have come on hard courts, and the only one to have taken place at a Grand Slam was the final of the 2019 US Open, which Nadal won in five sets having initially surrendered a two-set lead.
We say: Medvedev to win in five sets
There have been a few apparent 'passing of the torch' moments in recent tennis history, but the age-defying brilliance of Federer, Nadal and Djokovic has so far exposed those as false dawns.
The same could be true this weekend if Nadal claims Grand Slam number 21 - and simply reaching the final shows that his time at the top is not over yet - but Medvedev is showing more and more signs of being the main contender to muscle in on the dominance of the 'big three' on a consistent basis.
Back-to-back Grand Slam titles is a major achievement in this golden era especially and, while some may point to the absences of both Djokovic and Federer, Medvedev is on the brink of doing something that no-one outside those three has done for more than two decades.
Many expected Medvedev to be there or thereabouts at the end of this tournament, while the same perhaps cannot be said for Nadal, which is already a major narrative change to when they met in the 2019 US Open final.
The Russian is much more at home on this stage than he was then - and even than he was in last year's Australian Open final - and we are backing him to come out on the right side of the contest this time.