No.1 seeds Barbora Krejcikova and Katerina Siniakova have clinched their fourth Grand Slam women's doubles title as a team.
Ash Barty won the match 6-3, 7-6 (7-2) to end a 44-year wait for an Australian to win their home Grand Slam.
Medvedev was all heart and legs to enter his second consecutive Australian Open final but finds Spanish ace Rafael Nadal on his way to glory.
A win over Medvedev will give Nadal a record-breaking 21st Grand Slam title. It will help him overtake two of his main competitors - Roger Federer and Novak Djokovic.
The reward for his last-four win on Friday is a mouth-watering summit clash against Rafael Nadal in Melbourne.
The victory is Kristina Mladenovic's first mixed major crown in eight years, her third overall and second in Australia.
Under the lights on Rod Laver Arena, the second seed showed a mix of quality and grit in defeating fourth seed Stefanos Tsitsipas 7-6(5), 4-6, 6-4, 6-1.
Playing under the roof on Rod Laver Arena, Nadal was in complete control for two sets and recovered from losing the third.
Swiatek, who was defeated by the American 6-4 6-1 in 78 minutes, also advanced to the semi-finals of the tune-up event in Adelaide.
On Thursday, the unseeded finalists upset the third and second seeds, respectively, in the Australian Open.