Tennis star Novak Djokovic has had his Australia visa revoked, casting serious doubt on his chances of winning his 21st Grand Slam title.
A legal challenge is now the only option for the world's number one male tennis player to defend his title.
What was meant to be the start to another Grand Slam campaign has escalated into a global controversy.
Here's how it has played out so far.
News that Djokovic had been approved to play in the Melbourne tournament, beginning on Monday, was revealed by the player himself on 4 January.
Australia requires all foreign visitors entering the country to be double vaccinated. Otherwise, they need to complete 14 days in quarantine. But Djokovic, who is unvaccinated, said on social media he had gained a medical exemption.
It was granted by two independent medical panels organised by Tennis Australia and Victoria state.
The announcement sparked public outrage in Australia, especially as residents have been living amongst some of the toughest lockdowns and restrictions since the pandemic began. Most have followed government directions to get vaccinated, and over 90% of the adult population is now double-dosed.
Australian Prime Minister Scott Morrison initially said he would let the Victorian state government decide the matter. But he later backpedalled and said the final say would remain with the federal government and Australia's immigration authorities.
The arrival in Australia
Djokovic arrived at Melbourne's airport late on 5 January. In a dramatic twist, his entry was rejected by border officials in the early hours of the following morning.
His visa was cancelled on the spot and the Serbian tennis player was taken to a notorious immigration detention hotel, where he remained for five days.
Many in Australia cheered the move, but equally it sparked an uproar among supporters who gathered outside his hotel, as well as in Serbia. President Aleksander Vucic accused Australia of "harassing" Djokovic - a claim denied by Canberra.
Djokovic's family also complained, accusing the government of treating the tennis player like "a terrorist in Guantanamo Bay".
Meanwhile Djokovic's legal team speedily launched a challenge to the visa cancellation.
The hearing - and release of Djokovic
On 10 January, an Australian court heard arguments from both the government and Djokovic's lawyers.
Djokovic's legal team made several arguments, but the most crucial one was that the tennis player had been treated unfairly when he arrived. They pointed out how immigration officials refused Djokovic's request to wait until 08:30 local time to contact his lawyers and Tennis Australia, before proceeding with the visa cancellation.
They argued this was grounds for "legal unreasonableness" and denial of "procedural fairness".
The government's legal submissions had countered that he had enough time to explain his case. But during the hearing, it conceded on the point made by Djokovic's team.
Judge Anthony Kelly ultimately agreed with Djokovic's lawyers, ruling he was denied "fair opportunity" to respond adequately, and quashed the visa cancellation.
The tennis star was allowed to walk free immediately, and the government was told to pay all legal costs.
Fresh questions and Djokovic's response
The court documents - as well as Djokovic's travel declaration form, made public in Australian media - have revealed other things.
They confirmed Djokovic is not vaccinated - his status was not previously known - and that he's caught Covid-19 twice, with the latest positive test on 16 December.
The documents ended up prompting fresh questions.
Many pointed out social media posts showing Djokovic attending public events and doing an interview with a French publication in the days immediately after he had tested positive.
Djokovic, who had flown in from Spain via Dubai, had declared to Australian authorities that he had not travelled anywhere else in the 14 days prior. But posts showed that he had been in Serbia during that period.
On 12 January, two days following his release from detention, Djokovic posted a statement on Instagram to clarify "ongoing misinformation" about his movements.
In it, Djokovic admitted that mistakes were made on his immigration forms, for which he blamed an agent. He also said he had met a French journalist and removed his mask for a photo shoot despite knowing he had Covid, breaking isolation rules.
"On reflection, this was an error of judgement and I accept that I should have rescheduled this commitment," he wrote in the post.
The re-cancellation of the visa
On 14 January Australia's Immigration Minister Alex Hawke announced that Djokovic's visa was cancelled on "health and good order grounds, on the basis that it was in the public interest to do so".
The tennis star now faces deportation, but it is likely he will mount a second legal challenge in a last-ditch attempt to preserve his chances of participating in the Australian Open.
Djokovic's lawyers are reportedly hoping to expedite any fresh hearings and see them concluded over the weekend, which would clear the way for him to compete in the tournament.
If they succeed, and Djokovic wins the Open, he will be the most successful men's tennis player of all time.
If they don't, Djokovic will be sent home in what would be an ignominious end to a tumultuous saga.