Royal Irish Regiment soldier 23-year-old Michael Wilson, from Marlacoo Road, Tandragee, and 24-year-old, Gareth McKinney, originally from Charles Park, Portadown, had been accused of the murder of 32-year-old Lee Smyth.
Wilson also pleaded guilty to robbing Mr Smyth of a cigarette tin after he was left unconscious in a pool of blood, almost unrecognisable, following a brutal attack on 6 June 2010.
On Wednesday following an adjournment as the Armagh Crown Court trial was about to enter its second day, defence lawyer Paul Ramsey QC, for McKinney, asked for his client to be re-arraigned.
Mr Arthur Harvey QC said he would have a similar application on behalf of Wilson.
As the murder charge was put to them again, both men continued to deny the murder, but in turn pleaded "guilty" to the manslaughter of Mr Smyth who'd had suffered a catastrophic brain injury, from which he never recovered.
Prosecution QC Terence Mooney told trial judge Mr Justice Weir and the jury of six women and six men, that he had considered the pleas to the lesser charge, following an earlier indictment, and in view of the evidence he was prepared to accept them in the interests of justice.
On Tuesday he had told the court that the attack was a result of the all too distressingly familiar story of young men emboldened by drink, who met and for whatever reason, then engaged in gratuitous violence.
Mr Mooney claimed that both McKinney and Wilson, free from all constraint, had engaged in a totally unwarranted attack on a defenceless Mr Smyth.
The court heard that Mr Smyth was found in the early hours in the Folly area of the cathedral city by a woman out walking her dog.
Although he survived in a coma for just over two years, his family made the agonising decision, based on medical advice, as he continued to deteriorate, to withhold further treatment.
Mr Mooney had also claimed that Mr Smyth had been treated "like a trampoline", with his attackers using their "shod feet" to jump on him as he lay prone, motionless and defenceless on the ground.
He also alleged a former girlfriend of McKinney would contradict his assertion that he was not involved in the attack, or Wilson's claim, that while present, he played no role.
However, in her evidence Ms Lindsay Bell revealed that it had been Mr Smyth who had "went for" Wilson, throwing the first punch as "they squared up to each other".
Although McKinney joined in the fight after she had asked him to intervene and stop it, she added that Mr Smyth was punched and only kicked "on his body".
Ms Bell, who began her evidence in tears, shaking almost uncontrollably, said that when all three men were fighting, McKinney and Wilson "got the better of the bald man" who wasn't responding as much when he was fighting with Wilson alone.
Wilson, she said, didn't seem to know what was going on, "with the adrenalin", and that "it ended up being just more than a fight", and that Wilson had kicked him "on his body", and that McKinney was also involved, although he did not use his feet, and that the fight "just stopped".
Later Ms Bell also agreed with Mr Harvey that even after Mr Smyth's unfortunate death, Wilson "still did not appreciate it was connected with what happened on that path on that day".
The court also heard that in the hours before the attack, Mr Smyth had been involved in two other disputes and had been told to go home by police officers.
Both Wilson and McKinney will be sentenced next month, and while McKinney was released on continuing bail, Mr Justice Weir said it in no way could be taken as indication that he would not inevitably face a custodial sentence.