Now, police hunting the attackers have made a major breakthrough after a Napier resident recovered a knife.
Detectives believe it is linked to the stabbing, which happened on the corner of McDonald St at around 2am.
Acting Detective Senior Sergeant Emmet Lynch said the large kitchen knife will be forensically examined over the next few days but was "confident'' he had a match.
He said: "We can't categorically say it is the one, but considering its closeness to the scene and the type of weapon, the blade, and injuries inflicted, we're pretty confident with it.
"It will be subject to forensic testing over the next few days to clarify that but it's a real positive step.''
Mr Lynch said the find came after a public appeal last night for homeowners in the area to check their properties for a weapon.
He added: "This lady had a look and found the knife in the backyard of her address.''
The 22-year-old friend, who was also attacked, was not badly hurt, and had been assisting police with their inquiries, Mr Lynch said.
The detective said the gang of attackers were unknown to the men and there had not been "previous knowledge or dealings'' with them that evening.
He said: "These two guys had been in town watching the fireworks display in Napier city. They then walked down the main road towards the residential suburbs and walked past a group of males who they didn't know.
"The males immediately started to follow them, accosted them, and started the attack.
"There was certainly no previous knowledge or dealings with them, so it was quite a random thing.''
Police are still appealing for witnesses to come forward, especially a young male who came to the stabbing victim's aid, as well as a "well-dressed male'' who was also at the scene.
Mr Lynch said officers were still trying to establish a motive for the attack.
He said: "We're starting to get some good information now from people who were in the area at the time - what parties were going on, and what connections they may have had with this group.
"We're still talking to as many people as we can and, certainly motive is one of the key things we're considering.''