Glasgow's was memorable for two very contrasting reasons. For the Warriors as a whole, it was a sign of things to come under Franco Smith: the head coach had chosen what on paper was an understrength side for the trip to the Recreation Ground, but in fact got his selection spot-on.
Mann impressed on his debut - a 22-19 Challenge Cup win over Bath in December 2022 - but it was cut short when the back row man suffered a concussion. As a precautionary measure Mann was sidelined for a year and then, just two weeks after resuming training, he suffered a serious ankle injury in a training match.
Mann returned to action towards the end of last season with a couple of games for the Warriors' 'A' team but now he's wanting to make his mark for the senior side starting a week on Saturday, when the team travel to Italy for a pre-season friendly against Zebre.
"I was so grateful to be involved in that game against Bath," Man told The Offside Line. "But obviously in the 60th minute I got that concussion, which then spilled into last season, because I was out for a year with that. Came back in December, and then two weeks later my ankle got blown to pieces.
"I then came back with a month and a half, two months, left in the season. I played in a couple of 'A' games. Unfortunately I wasn't involved in any knockout rugby or anything like that - but to be honest I wasn't really expecting to be, having been out for so long.
"It wasn't so much that I had any problems with my symptoms or anything like that, it was that I'd had three concussions in that year," Mann continues when asked why his head injury against Bath occasioned such a long break. "The normal stand-down for that would be three months, but if I got another concussion within a year after those three I would be out for six months.
"So the thinking was if they put me on that [year-long] stand-down, because of the World Cup I would only miss four or five games of the 2023-24 season. That thinking actually worked out quite well. But it so happened that the cards fell as they may and I broke my ankle two weeks after coming back."
While recovering from that ankle damage, Mann signed a new contract with Glasgow in March. He now wants to repay the club's faith in him.
"That's one of the main reasons I'm so keen to get out there and play," he continued. "I really want to reciprocate that to the club, because I feel like they've put so much faith in me based on one game.
"It feels a bit bad that I've been sponging off them for the last year and a half."
Mann is eager to make up for lost time, but his experiences means he knows that he can take nothing for granted - especially given the depth of competition in his position.
"I'm very much targeting this season and want to kick on, but at the same time it's sport and you can't predict anything. If I was to get another injury or something like that, then so be it.
"I'm very realistic about the competition in my position - it's pretty crazy. I'm not saying that I want to go out and play the next 25 games for Glasgow - but as many games as I can get possibly, really. Any game would be an improvement on last season."