In her opening address, Crown solicitor Mary-Jane Thomas said there was a fight between "drunk, stupid and young men".
The two complainants were part of a group of eight people from Wellington who travelled to Queenstown for a ski trip.
After drinking at a bar until 2.15am, the group were walking back to accommodation when they passed Harrington and the group he was with in Beach St.
Someone from the complainant's group made a "dumb comment" about a hat, which sparked an argument and the fighting ensued, she said.
CCTV footage would be shown to jurors, and Thomas asked them to have a close look at the attitude of the defendant.
At one point, the jury would see Boe running towards a man in Harrington's group before hitting him over the head with a bottle, she said.
Thomas said his behaviour was inexcusable — he was charged and dealt with in court.
Next in the incident, Harrington rushed in, pulled out a knife and stabbed Boe four times, before stabbing Nielson and fleeing.
The jury was asked to determine the level of violence applied and the circumstances surrounding the incident.
"I want to be really clear. When we're talking about stabbing, the injuries, we are not talking about little scratches.
"The Crown says this was a serious stabbing."
Both complainants were flown to Dunedin Hospital for surgery — Boe sustained lacerations to his liver while Nielsen had them to his stomach and a wound to his bladder.
Thomas said that a day later, on August 19, Harrington flew to Australia but was detained in Sydney.
He returned to New Zealand where he declined to make a statement.
While the Crown had to disprove the stabbings were in self defence, she argued the act was done for the sake of a fight.
Defence counsel Bill Dawkins said there was no denying it was Harrington who stabbed the men.
However, what he was challenging was the intention.
"Both ended up with serious injuries, you've got that, but this was not his purpose," Dawkins said.
"That is not what he had on his mind in the split second that he acted on both occasions."
He asked jurors to look carefully at the case "through the lens" of the defendant — what the circumstances were, from Harrington's point of view, and what he was confronted with when he had the knife.
The trial is expected to last four days.