Glasgow produced the shock of the round with a 21-17 victory over Leinster in the Magners League at Firhill on Friday.
Glasgow's quest to make it two home Magners League triumphs on the trot had looked set to be wrecked by the boot of Jonathan Sexton.
But full-back Bernardo Stortoni barged over in the fifth minute of stoppage time to steal the glory.
The opening sparring session was predictably scrappy and disjointed with both sides making a spate of basic mistakes.
The visitors were the first to establish any kind of rhythm and they edged in front with a penalty by Sexton from 30 metres.
Leinster continued to hold the upper hand without looking like making a significant breakthrough.
And they had to rely again on the boot of Sexton to increase their advantage in the 25th minute when Glasgow were guilty of handling in a ruck.
The bulk of the action was being fought out in midfield but the Warriors got up and running on the half-hour mark when stand-off Colin Gregor clipped over a smart drop-goal.
Gregor was back in the spotlight on the brink of the break but this time it was for negative reasons as he sent a penalty attempt wide of the target after Andy Newman had been illegally challenged at a line-out.
Glasgow forwards coach Shade Munro sent World Cup hooker Fergus Thomson into the fray immediately after the restart in place of Eric Milligan.
The switch seemed to inspire the Warriors and within four minutes they surged ahead thanks to a try by prop Moray Low following a pack drive.
It was a moment of joy for the front-row youngster, who had seen a score chalked off earlier.
Leinster shrugged off the setback to snatch back the initiative as Sexton completed his penalty treble.
And he delivered another dent to the Glasgow morale by adding a drop-goal to his tally.
Gregor set up a tense finale by thumping over a 25-metre penalty.
Cian Healy put Leinster back in control when he pounced for a try against the run of play.
But substitute Hefin O'Hare went over at the other end to give the Warriors a fresh dose of hope.
And then Stortoni was in the right place at the right time to settle the issue.
Tries: Low, O'Hare, Stortini
Drop goal: Gregor
Pens: Sexton (3)
Drop goal: Sexton
Glasgow: 15 Bernardo Stortoni, 14 Max Evans, 13 Graeme Morrison, 12 Daryl Gibson, 11 Thom Evans, 10 Colin Gregor, 9 Sam Pinder, 8 Johnnie Beattie, 7 John Barclay, 6 Stevie Swindall, 5 Alastair Kellock (c), 4 Andy Newman, 3 Moray Low, 2 Eric Milligan, 1 Ed Kalman.
Replacements: 16 Fergus Thomson, 17 Michael Collins, 18 Dan Turner, 19 James Eddie, 20 Chris O'Young, 21 Scott Barrow, 22 Hefin O'Hare.
Leinster: 15 Ross McCarron, 14 Luke Fitzgerald, 13 Shane Horgan (c), 12 Christian Warner, 11 Rob Kearney, 10 Jonathan Sexton, 9 Cillian Willis, 8 Kevin McLaughlin, 7 Shane Jennings, 6 Stephen Keogh, 5 Devin Toner, 4 Cameron Jowitt, 3 Stephen Knoop, 2 Bernard Jackman, 1 Stan Wright.
Replacements: 16 Brian Blaney, 17 Cian Healy, 18 Malcolm O'Kelly, 19 Keith Gleeson, 20 Chris Keane, 21 Fergus McFadden, 22 Fionn Carr.
Venue: Firhill, Glasgow
Referee: Hugh Watkins (Wales)
Touch judges: Neil Paterson (Scotland), Peter Carruthers (Scotland)
Television match official: Peter Allan (Scotland)