Harry Mallinder’s last-minute try not only won the youngster the man of the match award on his European debut but also kept the Saints’ Champions Cup hopes alive.
After a frustrating evening in which Saints had scored the tries but not been able to string together the phases to put Glasgow away, the replacement was in the right place at the right time to collect George North’s tap-down of a pin-point Stephen Myler cross-field kick to score unopposed and bring Franklin’s Gardens to its feet.
Gregor Townsend’s men will no doubt be heading back to Scotland annoyed that they had not been able to close out what would have been a hard-fought win, yet it was the hosts who bookended the game with the tries.
Glasgow had the first chance of points, Stuart Hogg hooking a long-range penalty left, but it was Saints who had the better start, sending a series of penalties to the touchline in search of tries. And that was exactly what they got, as the Warriors failed to deal with the technical ability and rolling mauls set up by the hosts.
Initially this was the source of the repeated penalties, and it ended up providing the opening try, too, Teimana Harrison coming up with a classic ‘quarter back sneak’ over the final inches for the score.
Both teams were showing their intent, but while they both had their chances in the opening quarter they were not able to convert them into points, Glasgow turning over a dangerous-looking attack from Saints, before coughing up the ball at the other end.
With Finn Russell joining Hogg in missing a shot at goal - albeit one considerably more straightforward than the full back - the Warriors were not capitalising on an off-loading game which was asking plenty of questions of the home defence.
That changed in the 24th minute, Russell getting his team on the score board, and this prompted a spell of concerted pressure from the Warriors, who went through phase after phase before sending a penalty to the corner.
North may have been a shade unlucky to have been penalised after being wrestled over the breakdown, but the defence was up to the challenge, holding up the maul and then turning the ball over after stopping repeated phases.
Unfortunately Hanrahan’s clearance was not good, and this was compounded first by the fly half coming offside to create the chance for Russell to reduce the deficit by three, and then sending the kick off out on the full.
This meant that Glasgow were able to spend the majority of the remaining minutes in Saints’ half. But nevertheless it was the hosts who had the opportunity to finish the first 40 with more points, sending a penalty to the corner for one last drive.
But Glasgow held out, and hit the front for the first time seven minutes after play resumed, Russell - at the second attempt - nailing a three-pointer from in front of the sticks.
The Warriors were worth their lead, keeping possession patiently and getting onto the front foot repeatedly, either through the likes of Hogg’s dancing feet or Leone Nakawara’s ability to work his hands free and get the ball away.
This gave Saints a kick up the backside, and when they got a break after Russell fumbled a huge up-and-under from Mallinder they capitalised to the full. Glasgow defended the initial attack reasonably well, but an infringement at a breakdown saw the ball sent to the corner and the pack do the rest, Christian Day coming up with the ball.
Russell tied things up almost immediately, but back came Saints, only to be frustrated once again.
Good hands set up Mallinder to go down the right wing, but the final desperate tackle both felled the replacement and gave Glasgow the chance to scramble back to such an extent that they not only held out what Saints had to throw at them but also win a penalty after an isolated Lee Dickson held onto the ball too long.
The Warriors’ defence was also strong enough to hold out another maul five metres out, and their work on the back foot was rewarded 10 minutes from time when Hogg hit the target from 45 metres out.
But then Saints were handed what would be the crucial boost. In the middle of a Glasgow maul Tim Swinson was spotted swinging a punch into Mikey Haywood, the replacement being sent to the sin bin for a few minutes of contemplation.
The penalty was kicked deep, and then another kicked to the far touchline. Backs were sent in to shore up the forwards, but this left the space outside, and the trio of Myler, North and Mallinder did the rest.
SAINTS Foden; Collins, G Pisi, Burrell, North; Hanrahan, Dickson (capt); A Waller, Hartley, Hill, Lawes, Day, Gibson, Wood, Harrison
Subs - Haywood, E Waller, Denman, Paterson, Fisher, Kessell, Myler, Mallinder
GLASGOW Hogg; Jones, Dunbar, Johnson, Lamont; Russell, Price; Reid, MacArthur, Puafisi, Nakawara, Gray (capt), Wilson, Fusaro, Ashe
Subs - Mamukashvili, Allan, Fagerson, Swinson, Favaro, Hart, Weir, Naiyaravoro
2mins GLAS Miss pen Hogg
9mins SAINTS Try Harrison Con Hanrahan 7-0
12mins GLAS Miss pen Russell
23mins GLAS Pen Russell 7-3
32mins GLAS Pen Russell 7-6
HALF-TIME SAINTS 7 GLASGOW 6
43mins GLAS Miss pen Russell
47mins GLAS Pen Russell 7-9
51mins SAINTS Try Day 12-9
56mins GLAS Pen Russell 12-12
70mins GLAS Pen Hogg 12-15
74mins GLAS Yellow card Swinson
79mins SAINTS Try Mallinder Con Myler 19-15
FULL-TIME SAINTS 19 GLASGOW 15