“I see life as a great learning curve,” Djokovic told CNN in an interview last year, “and I feel over the years I learned how to bounce back.”That ability to bounce back will be put to the test in the coming days as the world No. 1 prepares to defend his Australian Open title after a turbulent start to the year.Arriving in Australia unvaccinated but with a medical exemption to compete following a positive Covid-19 test on December 16, Djokovic spent his first five days in a detention facility in Melbourne as he mounted a legal challenge against the revocation of his visa. After his lawyers successfully argued that Djokovic had “ticked absolutely every box” for vaccine exemption with his recent Covid infection, he said his focus remains on competing in the Australian Open.Were the 34-year-old Serbian to triumph in this year’s tournament, one he has won on nine previous occasions, then Djokovic would move clear of Rafael Nadal and Roger Federer at the top of the men’s all-time list with 21 grand slam titles. It would arguably be the crowning achievement of Djokovic’s already record-breaking career — the moment he cements his status as the best player in the history of the men’s game. “Strictly speaking about results, Novak Djokovic is the best player in the history of men’s professional tennis,” said journalist Ben Rothenberg. “He’s tied with Federer and Nadal for the most grand slam titles, but Djokovic dominates pretty much every conceivable tiebreak category: most weeks ranked No. 1, a winning record against the other two, having won every grand slam and masters 1000 event at least twice (no one else has won them all once, even).”Djokovic is a counterpuncher with a great serve, an extraordinarily flexible athlete, and though he probably isn’t a popular pick for the most stylistically pleasing player ever, when it comes to who is the most effective and dominant on court over the longest period of time, he’s your guy.”Djokovic’s phenomenal record at the Australian Open, which includes winning the title five times in the past seven years, makes him the favorite ahead of this year’s tournament, even taking into consideration his spell in detention.Nadal stepped up his return from injury last week by winning the 89th title of his career at the Melbourne Summer Set 1 tournament, while Daniil Medvedev, who beat Djokovic in last year’s US Open final, Alexander Zverev and Stefanos Tsitsipas will also be contenders for the title. ‘Novak is Serbia, and Serbia is Novak’But few would bet against Djokovic, who has received vociferous support from his fans — in Melbourne as well as back in his native Serbia — during the course of his visa saga.Crowds gathered outside Melbourne’s Park Hotel in protest against Djokovic’s residency there last week, while chants of support were heard outside the office of his lawyers after he was cleared to stay in Australia. There were similar scenes outside Serbia’s National Assembly in Belgrade, where the tennis star was hailed as a national hero by his family. “They are holding him captive. Our Novak, our pride,” Djokovic’s father, Srdjan, railed in support of son last week. “Novak is Serbia, and Serbia is Novak … They trample Novak, and so they trample Serbia and the Serbian people.”Despite the ardent support of his fanbase, Djokovic remains a divisive figure — within the tennis community and beyond. He has spoken of his opposition to mandatory vaccinations, and the decision to grant him a medical exemption for the Australian Open was met with criticism; Stephen Parnis, one of the city’s prominent emergency physicians, said it sent “an appalling message to the public.” “I’m not an expert, of course, and I’m not going to talk about what are the pros and cons of getting vaccinated,” Djokovic told CNN in August, “but I am a proponent of freedom of choice.”He added: “I really believe that it should be left to a player to make a decision.”We don’t know what the future holds. I don’t think any industry is really certain what the future brings.”We are going to make sure that we gather as much expert information on this (as possible) and work with players and provide whatever information is needed for them to make a conscious choice.”Meanwhile, questions have also been raised about Djokovic’s actions in the aftermath of his positive Covid test last month. In a sworn affidavit published by Australia’s Federal Circuit Court on Monday, Djokovic said he knew about the positive result on December 16 but was pictured unmasked at events over the next two days. When his family were asked whether Djokovic had attended an event on December 17, his brother Djordje did not answer and swiftly concluded the media conference. ‘I still have my fears, my insecurities’It’s not the first time Djokovic’s actions have been questioned during the pandemic. In June 2020, his Adria Tour exhibition event was canceled after he tested positive for Covid-19 alongside his wife, three other players, three coaches and one player’s pregnant wife. Unlike other tennis tournaments held at the time, there was limited social distancing on the Adria Tour, which was played in crowded stadiums with players hugging and high-fiving each other. “I am so deeply sorry our tournament has caused harm,” Djokovic said after his positive test, adding that the charity event was organized “with a pure heart and sincere intentions.” Nine months prior to the Adria Tour, Djokovic landed himself in hot water as he was defaulted from the US Open for striking a line judge with a ball. He again apologized and said he was left “sad and empty” by the situation. Speaking about that period in an interview with CNN last year, Djokovic reflected on lessons learned. “I’m still a human being like everyone else, I still have my fears, my insecurities, I still make mistakes and errors,” he said. “Tennis, it’s kind of my learning ground. My strongest, most beautiful emotions surface there, but all the worst of my emotions surface there.”During and beyond this year’s Australian Open, it’s likely that Djokovic’s stance on vaccines will continue to be scrutinized. According to the ATP Tour, he is one of three unvaccinated players ranked in the 100. “Djokovic’s legacy is massively complicated and getting more so,” said Rothenberg”For all of his professionalism and his generosity (he’s great with charities and in interactions with his fans) his judgment often gets him into trouble, often straying him … toward fringe ideas, like his recent anti-vaccine commitment.”So much of tennis is about personalities and grace on and off court, and Djokovic has repeatedly sabotaged himself in these areas.”CNN has contacted Djokovic’s representative for comment numerous times ahead of the Australian Open but has not received a response.Djokovic won his first grand slam title at the Australian Open in 2008, after which he had to wait three years for his next major triumph, again at the Australian Open. Grand slam titles — 11 in total — came thick and fast in the six-year period between 2011 and 2016, culminating in Djokovic claiming the “Nole Slam” as the defending champion of all four grand slam tournaments at the same time. But an elbow injury in 2017 derailed Djokovic’s progress. His initial unwillingness to undergo surgery frustrated his former coach Andre Agassi, who told The Guardian he thought Djokovic had hoped his elbow would “heal naturally, holistically.”Djokovic eventually opted for surgery in early 2018 and returned to the court a few months later, but it was a setback that had almost led to him quitting tennis altogether. “To do the surgery, it was against his core values,” his wife Jelena told CNN in 2019. “It was really huge, it’s like he buried one part of him with that decision. He said: ‘I’m done, I’m not playing tennis anymore, I lost this, I’m not having fun anymore, this is it.'”Since that elbow surgery, Djokovic has won eight grand slam titles across a four-year period, eventually equaling Federer and Nadal’s record at Wimbledon last year. Many see it as only a matter of time before he owns the record outright and establishes himself as the greatest player in the history of men’s tennis — a titan on the court with a complicated, controversial legacy off it.CNN’s Christina Macfarlane, Don Riddell, Ben Church and Hannah Ritchie contributed to reporting.