Rublev, who had drawn criticism for suggesting he flew to Australia while infected with Covid-19, was beaten by Croat Marin Cilic
The World number six's hopes of his first Grand Slam win have again been derailed after the 24-year-old Moscow native suffered a shock defeat to Cilic, the former Australian Open finalist who earned just his second win against a player ranked in the top ten since 2018.
Cilic was in imperious form throughout, taking the win by a score of three sets to one, 7-5, 7-6(3), 3-6, 6-3, on Margaret Court Arena, and sending Rublev home just hours after he issued a clarification of comments which appeared to suggest that he had entered Australia while Covid-positive.
"It is incredible," said Cilic afterwards. "I enjoyed every single second of the match. Andrey is an incredible player, we have played several times in the past and it is always difficult. I had so much fun and played great tennis.
"In the evening it is a little bit cooler, so you can go for a bit more on your shots and it really went well for me," he added. "I served great and that is the way to go against the guys at the top. If you are giving them a chance to hit, you will have trouble, so I was trying to be aggressive and it paid off."
Rublev, meanwhile, faces the agony of defeat - as well as an inquisitive media eager to question comments he made to EuroSport in which he suggested he arrived in Australia ahead of the tournament while infected with Covid-19, something which is a very hot topic down under given the recent scandal involving Novak Djokovic.
"I personally do not test now, since I just got sick," he said this week when asked about the Australian Open Covid testing regimen.
"When I flew to Australia, I was still positive, but the level of Covid SS [severity score] - as it is called, I will not lie - was very low and harmless, and I was allowed in. Plus, I spent more than 10 days in quarantine," the fully-vaccinated player added.
"Upon arrival, I had to take an antigen test, I passed it, it was negative, and I did not do a PCR test. Perhaps it would still show positive. But I'm no longer contagious and dangerous. Since I was ill, I no longer do a PCR test."
However, seeking to address the controversy ahead of his match with Cilic Rublev said that all of the necessary health and safety protocols were correctly observed.
"I started training a few days before my flight to Australia," Rublev stated. "The team and I flew to Melbourne, observing all protocols. Quarantine was over, vaccinations were delivered. We immediately passed the antigen test. The result was negative. So I could move freely.
"By the way, before Australia, by the end of quarantine, all my antigen tests were also negative. And before the flight to Melbourne, the tests were also negative.
"Despite this, I was quarantined for 10 days. All this time I was in touch with doctors, representatives of the tournament. I didn't break any rules," he said.
"I would never put other people's lives in danger. I am a person who is responsible for my actions. I am sorry that the published information sometimes loses its meaning, and my previous story turned out to be very crumpled. I hope now I have managed to convey my thoughts correctly."