It helps that Medvedev slaps relatively flat returns and passing shots compared with a player like Nadal, whose dipping topspin can make it harder to hit decisive volleys. New paradigm? Probably not, but it was certainly effective indoors on Sunday despite the relatively heavy balls that, in theory, should have made winners more difficult to produce.

“He puts a lot of returns back in play, and he’s just so good at staying in the point and making you suffer and forcing you to do an unforced error,” Djokovic said. “So you have to have in a way controlled aggression against him.”

He added, “I wanted to keep him on his toes, so he doesn’t know what’s coming up next, to be a little bit unpredictable.”

It is surely easier to surprise Medvedev at this early stage of their rivalry than men whom Djokovic has faced for more than a decade, like Nadal and Federer. But though Djokovic and Nadal had a memorable duel this year in Paris, with Djokovic prevailing in a four-set semifinal, Djokovic versus Medvedev has been the most compelling rivalry of the year.

Djokovic beat him in straight sets in the Australian Open final, lost in straight sets in New York and then won their best match yet in Paris. It would be no surprise if they met once more this year at the ATP Finals in Turin, Italy, which will begin on Sunday on another indoor hardcourt.

They have become increasingly comfortable with each other and even trained together recently near their Monte Carlo residences: a rare occasion for a No. 1 and No. 2 player. Their meeting at the net after Sunday’s final was full of warmth despite Medvedev’s disappointment, and Djokovic has perhaps never applauded an opponent’s winners as often as he did for Medvedev’s in Paris. That was in part because the level was so high, particularly when they were locked in baseline exchanges that both were able to extend far beyond the norm with their extraordinary defensive skills.

“He’s probably my biggest rival in tennis at the moment,” Djokovic said.

The question is whether either of them will make the long trip to Melbourne for the Australian Open, where the state government of Victoria has indicated that players will be required to be fully vaccinated for Covid-19. According to the ATP Tour, 25 percent of the top 100 singles players remain unvaccinated. Djokovic, who contracted the coronavirus in 2020, and Medvedev have declined to disclose whether they are vaccinated. Both said in Paris that they would decide whether to play the Australian Open after the tournament made its formal policy clear.

“I don’t want to be part of the stories about the assumptions and what ifs,” Djokovic said. “When the official conditions and requirements to travel to Australia and play in Australia are out, then obviously I will see what I personally do with that, and also the bigger group of the players. Because the situation is obviously different in Australia than most parts of the world.”

The announcement is imminent, according to Tennis Australia, which will officially launch the tournament next week with tickets going on sale on Nov. 19.

Skipping the trip would be no small sacrifice for Djokovic, who is in pursuit of a 21st Grand Slam singles title to break his three-way tie with Federer and Nadal. Djokovic, a nine-time Australian Open champion, has won nearly half of his majors on the hardcourts in Melbourne. Though he remains No. 1 after another brilliant and resilient season, he can sense the pressure from below from Medvedev, 25, and his peer group, who have no children in tow just yet.

“He’s the leader of the next generation,” Djokovic said. “They are already there, and they are challenging the three of us old guys, and we’re going to try to hang in there.”