Warriors ran out 40-31 winners with a number of young players making their mark on the game.
"It's definitely good to be back," McKay told glasgowwarriors.org at full-time.
"It feels like ages since we last played at Scotstoun. It's good to be out at home, back in front of our home fans."
McKay weighed in with Glasgow's final try but also took pride in the impact made by the young Warriors.
The full-back's try was the product of good work by academy duo Matthew Urwin and Fergus Watson and rounded off an entertaining encounter.
"It was unreal," said McKay.
"I was pretty exhausted after the chase back and then the kick long. I was just on the fat man's track, catching up with the boys! Then I thought, 'oh jeez, Matty Urwin's going to be away here, I'd better catch up to him'.
"I was just able to trot it in after not doing too much hard work there - cheers to the young team for setting me up!"
McKay had words of praise for 20-year-old Fergus Watson, who earned Player of the Match honours.
"Absolutely buzzing for young Fergster - that's what he's nicknamed himself," said McKay.
"Nah I'm proud of him. To see his growth over the last probably two years, I've known Fergie. He's come a long way. He was pretty slippery out there."
Warriors had to come back from 14-0 down with Northampton controlling proceedings early on.
"It was a tough, very tough first 15 minutes out there," McKay admitted.
"We were put under a lot of pressure. It felt like we had no possession and no territory - pretty much nothing went right. Obviously we had a lot of young boys on the field, so it was good to actually gain a bit of parity back and claw us into a position to win the match, which is what we went on to do."
The resilience - refusing to fold under the weight of early setbacks - was perhaps the most encouraging aspect of the night.
"A lot of young boys had to stand up there," McKay continued. "It would have been really easy just to shy away from it and not dig in; not show the effort we needed. But they did dig in, and that's what got us back into the game.
"This summer's been good - weve put in some hard work the last couple of weeks," McKay said. "Tonight was about taking a step up from last week. And it's good to show a bit of a response, good to get that feeling of winning again in front of the home fans."