George Best remains critically ill on a life support machine in a London hospital and has not made any improvement since yesterday.
The soccer legend's doctor, Prof Roger Williams, said Best was still a "desperately ill man" but was tough and was keeping himself alive.
George Best at the height of his career
Prof Williams said yesterday he was worried about the former Manchester United player's condition and that the next 24 hours would be critical.
"There's not been any change whatsoever so obviously he's still unconscious," Best's agent, Phil Hughes, told reporters outside the Cromwell Hospital this morning.
"He's not looking well at all. His family are beside him," he said. Mr Hughes said the former Northern Ireland international had a comfortable night but said it was "absolutely the worst" condition he had ever seen him in.
Best (59), from Belfast, has been in hospital since the beginning of October. He was initially admitted to hospital after having a reaction to the treatment he was receiving for the liver he received in transplant in 2001. He then suffered internal bleeding linked to a bowel infection.
His condition improved over the past few weeks, although he remained in hospital. However, he suffered a downturn late last week and was readmitted to intensive care with a lung infection on Friday. He is now on a ventilator and is being treated with antibiotics, replacement fluids and clotting factors.
Prof Williams said doctors had now stopped sedation and were waiting to see if Best regained consciousness. Best's family have been trying to get a reaction from the ex-Northern Ireland player by talking to him, but he remains unable to communicate with those around him.
Prof Williams said yesterday Best's family was unlikely to be faced with the tough question of deciding whether treatment should continue for him. "I would imagine the situation will resolve itself naturally, that's what normally happens. It's not a case of switching off life support."
The 1968 European Footballer of the Year has had an alcohol problem for much of his adult life.
Yesterday, a picture of Best looking gaunt and yellow was published on the front page of the News of the Worldwith a message saying: "Don't Die Like Me".
The newspaper said Best had asked for it to be published as a warning to others about the dangers of excessive drinking. "George could never beat his drink problem, but he told me 'I hope my plight can act as a warning to others,'" Mr Hughes told the paper.