An American tourist had been in Queenstown two days before a drunken assault in the CBD which could have proven fatal for the victim.
Self-employed videographer Erik Anthony Armstrong (31), of California, yesterday admitted injuring Tatshuhito Sasakura with reckless disregard for the safety of others on January 5.
Sergeant Kate Pirovano, of Queenstown, described it as a "coward's punch'', which left the man unconscious and could have killed him.
The summary of facts said at 4am Armstrong was intoxicated in Searle Lane, along with a group of about 10 people, including the victim, after the nearby licensed premises had closed.
Armstrong and Sasakura did not know each other and were standing about a metre apart when "some words'" were exchanged between the two.
"Without any provocation, the defendant ... took a backward step, balanced himself, clenched his right fist, [and] made a direct, heavy punch to the victim's head, striking him directly on the face.
"The victim fell backwards, instantly unconscious, before he hit the hard ground."
Armstrong fled while Sasakura was looked after by others in the area until police arrived.
The American holiday-maker was found at a fast-food outlet a short time later and declined to make a statement.
Sasakura sustained a swollen lip which had been split open by a tooth penetrating it, and was monitored at Lakes District Hospital for several hours.
Prosecuting sergeant Ian Collin told Judge Dominic Flatley in the Queenstown District Court yesterday Sasakura also needed dental treatment - the "worst case scenario" involved a "nerve replacement" to a tooth.
Defence counsel Liam Collins said Armstrong had no previous criminal convictions, had withdrawn all the money in his bank account to cover a fine and emotional harm payment and had completed 37 hours' voluntary community work since his arrest.
Collins said Armstrong was "sickened by his actions".
"I've shown him the video - he is not impressed with himself.
"The poison was alcohol. He doesn't intend to consume it again.
"Despite what the media will term this, it was a single strike. There was no attempt to follow-up, there was no kicking or stomping.
"A single strike, yes, to the head, but that is where the confrontation ended."
Judge Flatley said Armstrong's offending fell into the top end of category one for the charge, which carried a maximum sentence of five years' imprisonment.
The punch "could have been fatal'".
"It caused the victim to fall backwards, instantly unconscious, before he hit the ground, hard.
"As you well know, that could have been extremely dangerous.
"People can be killed by one punch."
However, there were no other aggravating factors, and Armstrong was due to leave Queenstown last night and fly from Auckland tomorrow.
He had given $3115 to the court, in cash, yesterday, $3065 of it to go to the victim.
Judge Flatley remanded him at large until Thursday for confirmation that he had left New Zealand.