The 18-year-old’s 65th minute goal gave Northern a 4-1 lead over Queen’s Park in its Chatham Cup game, adding to two quick goals in the first half.
Muir finding the back of the net has become a common sight for the fans at Forrester Park this season.
The goal was Muir’s 20th of the season in all competitions.
That would be a decent haul by August, and is made even more impressive by the fact it is only halfway through the season.
It is part of what has been a significant turnaround for Northern in recent years.
The club now finds itself third in the ODT Southern Premiership and, while chasing Roslyn-Wakari and the Dunedin City Royals 2nds, has a firm goal of promotion to the Southern League.
Northern has also progressed to the third round of the Chatham Cup, being drawn against Green Island.
Muir was new to the team this year, having transferred from Roslyn-Wakari, after being swayed by a friend.
He said the run had been "very unexpected", although was quick to point out he was one piece in a bigger puzzle.
"I’ve had some very good coaches at Northern and very good team-mates that have helped me get most of these goals, or all of these goals," Muir said.
"If it wasn’t without them, I wouldn’t be able to do it. It’s just a very good environment at Northern and I’m enjoying it a lot."
It was Muir’s first year playing consistently at the top level, having played for both the second and first teams at Roslyn and Mosgiel.
A first-year economics and politics student, he left Otago Boys’ High School last year.
He spent his first and last year of school there, having moved to Wellington and attended St Patrick’s Silverstream in between.
While he had scored plenty of goals growing up, doing it in a men’s league was much harder.
He hoped there would be more to come, although did not want to put a number on how many more.
"Hopefully I just keep scoring. I don’t really have any target.
"I just want to keep doing my job for the team, hopefully. The main priority’s just winning games at the moment and try to qualify for the Southern League."
Northern coach Arran Wilkinson added that Muir was "a really good kid" and fitted with a young and hard-working team.
"He’s a really good player," Wilkinson said.
"He’s also a player who works for others. If he’s got boys around him and it’s going well, he’s a real asset to everyone around him.
"He’s not one of those goal scorers that waits for it to happen and scores at the end. He hunts them down — sometimes we have to calm him down with this pressing.
"Technically he’s very good, he’s good with both feet and a real hard worker."
