This has already been something of a breakthrough year for the Edinburgh swimmer, whose 21st birthday celebrations on Sunday offered a chance to relax after two of the most exhilarating days of his life. Long recognised as one of the up-and-coming talents in Scottish swimming, having been selected for his first taste of top international action at the Commonwealth Games in Delhi, McNally reached the final of the 200 metres backstroke at the World Championships this year, finishing sixth.
However, unlike Michael Jamieson, Hannah Miley and Robbie Renwick, his fellow Scottish participants in the Duel in the Pool, the youngster has not yet been subjected to the full weight of expectation of medal success at a major competition.
In many ways he is part of what can almost be seen as a key group of athletes across all sports at next year's Games, those who are just on the point of establishing themselves at elite level but need their edge to be tempered in the heat of battle over the next six months or so.
They are the ones who stand to gain most from any success they achieve at the Games in Glasgow and in turn represent the chance of the biggest return for Scottish sport in the decade or so to come.
It is in that context a weekend observation from the vastly more experienced Renwick should be seen. He pointed out that it is relatively rare for Scots swimmers to get exposure to the world's very best.
Combine that with the invaluable opportunity to witness Tollcross decked out in all its finery for a major event, and the chance to feel the impact of swimming in such an atmosphere at a home meet, and it hardly seems to matter that McNally was unable to make a telling impact this time around.
Not that he was by any means uncompetitive, coming up less than two-tenths of a second from gaining third place and a point in the 200m backstroke on Friday, before getting within 1.6 seconds of European team-mate and Commonwealth Games rival Chris Walker-Hebborn, who prevented an American clean sweep in Saturday evening's 100m backstroke.
He was far from down-beat afterwards, showing maturity in recognising just how much he has benefited not just from this competition, but from this year as a whole. "Having a home crowd here has given us an idea of what it's going to be like at the Games, which gives you confidence, knowing you'll be there with that home crowd cheering you on," he said.
"I can take away from this year how close I can be and that everything counts, every little skill. I just need to continue working on the things I have been: the strength training and the skills in the pool, like the underwater work."
While the likes of the Australians, South Africans and Canadians - as well as England - will ensure that there are no easy medals to be claimed in the summer, simply being part of a pan-European team competing with swimming's superpower was a confidence booster. So, too, was the result, as the Americans were properly challenged for the first time in the 10-year history of Duel in the Pool events, winning the tie-break race by just 0.2 of a second after the teams had finished level on 131 points after 30 races over two days of competition.
"It was really exciting," said McNally. "I thought the Americans looked very strong coming into it, but as the competition went on and we were ahead after the first day, we knew it was going to come down to the last couple of relays to decide it.
"We're still all really happy with that. Everyone swam really well and to come that close to the Americans this time was good. The Americans have won it each previous time by quite a margin, so hopefully we've caught up with them and next time we'll be able to come out on top."
This was, with Scotland's biggest ever year of sport now just little more than a week away, the perfect sparring session. "The Americans were some of the best swimmers in the world," pointed out McNally. "So they couldn't have offered us much better opposition to practise against coming up to the Commonwealth Games."