Elena Rybakina, who lost out to Sabalenka over three sets in Saturday's final in Melbourne, climbed 15 places to a career-best ranking of 10th.
Djokovic's 10th Australian Open title means he is world number one for the 374th week since July 2011.
It capped a remarkable comeback by the 35-year-old fourth seed, who missed last year's tournament when he was deported over his Covid vaccination stance.
Sabalenka has now won all 11 matches she has contested this season, with big-serving Rybakina the latest to succumb to her power game and new-found mental strength.
The 35-year-old Serb, who has won all nine of his previous finals at Melbourne Park, will return to world number one if he defeats the Greek third set.
It was the seventh Grand Slam doubles title by the Czech pair, who broke their Japanese opponents' serve in each of the first games of the sets.
She used 17 aces to overcome seven double faults, and she managed to break the big-serving Rybakina three times
It was de Groot's fifth Australian Open title and 17th Grand Slam singles trophy overall. Kamiji was the last player to beat de Groot — more than two years ago.
For Djokovic, it matters to be the best and he has a strong sense of his historical place in tennis. But he also keeps ploughing on through the highs and lows because it is "a great school of life".
There are not many athletes whose careers and outlooks have been forged by near-death experiences, but the 24-year-old world number four is an exception.
A pro-Russian YouTube account had posted a video showing Djokovic's father Srdjan posing in Melbourne Park with a fan holding a Russian flag that featured the face of Vladimir Putin.
In the junior girls singles final, ninth-seeded Alina Korneeva beat seventh-seeded Mirra Andreeva 6-7 (2), 6-4, 7-5 in a 3-hour, 18-minute baseline duel
Sania Mirza and Rohan Bopanna’s mixed doubles partnership at the Australian Open 2023 has been a spectacle.
Despite missing out on a title in her last Major event, tennis star's massive contribution to Indian sports, on & off the court, will always be remembered
He beats Paul 7-5, 6-1, 6-2 to close in on a 10th Australian Open championship and 22nd Grand Slam title overall.
Coming into her final Major tournament, Sania had three women's doubles and as many mixed doubles trophies in her cabinet.
Sabalenka came into the match as many observers' favourite for the Melbourne crown but she had never won a Grand Slam semi-final in three previous attempts.
The 22nd seed had already defeated reigning French and US Open champion Iga Swiatek in the fourth round and 2017 Roland Garros winner Jelena Ostapenko in the quarter-finals at Melbourne Park.
Serbian tennis reporters confirmed it was Djokovic's father and the Melbourne Age newspaper reported he said in Serbian: "Long live Russia."
Two-time Melbourne champion Victoria Azarenka, also from Belarus, will face Moscow-born Kazakh Elena Rybakina in the other semi-final.