Morrison (23) was the assistant referee, running the touchline in the ITM Cup match between Tasman and Otago, when he suddenly became the man in the middle, taking over from an injured Glen Jackson.
Morrison controlled the final 25 minutes of the match, making the most of his swift promotion.
The highest grade of rugby he had controlled previously were games between B representative sides, so it was a lofty rise on Sunday.
To add to the pressure was the fact he had just officiated in a game in Christchurch the day before so the frantic pace of Sunday's game not only had the lungs of the players burning.
"With that game in Christchurch on the Saturday the legs were getting a bit tired. In some ways it was faster and other ways it wasn't," Morrison said.
"It was totally unexpected and I did not have a lot of time to think about it really. I just had to step up and carry on. The game is not about me, anyway. It is about the players."
One advantage for him was he knew most of the players, having refereed the Otago players in club rugby, and having grown up in the Tasman area.
"They tested me for the first five to 10 minutes but the time seemed to go quite fast."
A bonus for Morrison was having his parents in the crowd, as they had come down to watch a game at the stadium and have a look around the University of Otago.
Jackson damaged his hamstring chasing a break downfield in what was a free-flowing match, and immediately knew he was in trouble.
Morrison said it was an early taste of first-class rugby and one he hoped to have more of.
He grew up in Marlborough and then went to Nelson College. A series of concussions led him into referring, rather than playing at high school, and he has never looked back.
"It is something I really enjoy doing. Everyone should have a go at it. You get to go places and hopefully, there will be more opportunities in the future."
Morrison, who is studying accountancy and anatomy at university, and is in his sixth year, said with most top-class referees not reaching their peak until their mid-30s, he had plenty of time left to progress.
