At the height of the Covid-19 lockdowns almost five years ago, Novak Djokovic and Andy Murray logged on to Instagram Live for a casual conversation from their homes. As some of their viewers began to send through questions, they were asked to list the first three things they do when they wake up. Djokovic went first: “Gratitude and prayer,” he said. “A couple of long, deep breaths. Hugging my wife if she’s still in bed and running to my children.”

Murray, who seemed to be fighting hard to maintain a straight face throughout Djokovic’s response, offered his own contributions: “For me, too much information, but I go for a pee.”

It is fair to say they are two extremely different people away from the tennis court, but for so much of the past 25 years their careers have been intertwined. Having first met 24 years ago while standing across the net from each other in Les Petites As, the prestigious under-14s event in France, the two players, born one week apart in May 1987, broke through on the ATP Tour around the same time and battled each other for years around the world on the biggest stages of their sport.

On court their similarities were undeniable, from the rock-solid defensive base and tireless endurance both players built in their games through to their unwavering commitment to their craft and intense demeanours. Even as Djokovic distanced himself from Murray with his superior achievements, eventually outpacing even Roger Federer and Rafael Nadal, the respect he holds for Murray as another of the best players of all time is eternal.

Still, as Murray made his final bow at the Paris Olympics last summer, it seemed that their pathways had diverged for good. During his short-lived period of retirement, Murray’s wife, Kim, and their four children could finally count on his constant presence after years of travelling around the world and making significant sacrifices in service of fulfilling his potential.

Away from the courts at last, the void left by his first obsession was quickly filled. Much of his past five months were spent on the golf course as he tried to fulfil his new long-term objective of becoming a scratch golfer. Murray even appeared at a tennis journalists’ golf tournament in October, where he briskly left with the trophy. He repeatedly sought out advice from fans on social media as he tried to improve his swing. The least surprising part of this new partnership is that Djokovic’s approach came while Murray was finishing a round of golf.

Throughout his career Murray has consistently shown a deep interest in the processes and motivations of other great athletes and so, after so many years of trying to outwit and outmanoeuvre each other while keeping their cards close to their chest, the prospect of entering into the world of one of his greatest rivals, sharing their philosophies and combining their talents to achieve more great things was too enticing to refuse. For both men, this experience so far has been unlike anything over the past decade.

“A very nice and strange feeling to have him on the same side of the court,” Djokovic tells the Guardian. “We’ve been rivals for 20-plus years and always kind of kept secrets from each other, the way we practised, the way we prepared, the way we approached the matches. Never wanted to show weakness to your main opponents, your rivals. But now it’s different.”

As they have navigated the grounds of Melbourne Park shoulder to shoulder this week, the unique nature of this partnership is not lost on their rivals: “Imagine Messi would become the coach of Cristiano Ronaldo,” said Danill Medvedev, smiling. “It would be strange.”

At the Qatar F1 Grand Prix in the final days of November, Djokovic weaved in and out of various team garages during a promotional appearance. During his time with the Mercedes team, Djokovic was taken by George Russell on a comprehensive tour of their technical room that handles the team’s elaborate data. “I felt like in Disneyland a little bit,” Djokovic says.

Alongside his well-publicised commitment to optimising his physical potential, the Serb has prioritised using data to improve his game throughout his career. In his formative years Djokovic’s first serious coach, the late Jelena Gencic, would take him back to her home between his tennis training and school lessons for further tennis study and she would stress the importance of video analysis in order to ensure he left no stone unturned in pursuit of success.

“Some players like to receive as less information as possible and kind of more follow their instinct automatically, just feel the opponent on the court, I guess. Some other players love going to the details. I’m more in the second group,” says Djokovic. “I really like data. Video analysis particularly. I’m quite a visual type of guy. I like to get a sense of patterns of play of my next opponent. I put throughout my career a lot of time and resources into that, along with my other team members.”

With his attention to detail and data, Djokovic has undoubtedly found a kindred spirit in Murray, who was also so committed to ensuring he eked everything he could out of his game.

During his career, the Scot would drive his own support team crazy with his determination to tick every box. Random scouting requests in the dead of night were not unusual and, like Djokovic, he utilised data constantly. There will be plenty of film nights to come.

Murray spent two decades building his reputation as one of the most intelligent players of his time. His game was cerebral, based on using his defence, shot tolerance and vast arsenal of shots to outthink his opposition. His preparation was so thorough that sometimes it was too thorough and he would overthink on the court. Having spent his time on the receiving end of information to accentuate those qualities, Murray 2.0 must learn how to navigate the other side and work with Djokovic to deliver to the player the information he needs.

“Hopefully, as a coach, I’m able to see the game through Novak’s eyes and help him with the right strategy on the court,” says Murray. “In many ways, we are quite similar characters, so I would hope I would empathise with him on the court when he’s finding it stressful or whatever, understanding those emotions, I can help with that. And if it was something I did longer term, I would hope I would improve as a coach as well: understanding when to speak, when to shut up, how best to communicate with him and his team.”

In the midst of a lengthy discussion about coaches, Frances Tiafoe defines a good coach as “a good motivator, who is not just telling you what to do. Working with you and creating more of a partnership rather than dictatorship”. In Djokovic’s case though, the dynamics are completely different. For a player of his stature and authority, it is all too easy to be surrounded by “yes men” who are afraid to be honest and blunt. “You get situations like that all the time,” says Tiafoe. “Guys are fluffing the truth, or kind of dancing around certain things to keep their jobs.”

Both Djokovic and Murray enter this partnership fully aware that, between Murray’s own historic success and the dynamics of a rivalry that has seen them push each other to their limits and constantly look to improve, the Scot has the authority to be honest and direct with Djokovic. “He’s gonna put everything into it,” says Tiafoe, who has a good relationship with both players. “He’s not just gonna come out here and just do nothing.

“It’s not celebrity coaching. He’s gonna want to actually be a great coach. He’s going to want to do right by Novak. It’s a pretty fun dynamic, but I think Andy hates losing as well so he’s going to be into it.”

Four days into their time together in Australia, it is clear that the work ethic Murray has applied for so long to his own career has been redirected to Djokovic’s cause. During the Serb’s numerous public training sessions, including practice sets against Carlos Alcaraz and Jack Draper, the communication between the pair has been ceaseless as they have learned more about each other, how they work and the best way to combine their attributes in order to make this partnership a success.

“So far [it] has been only positive experience for me, to be honest,” said Djokovic on Friday. “I’m very pleasantly surprised with his dedication and professionalism, considering he’s never had the experience of working as a tennis coach. It comes natural to him.”