It’s a run that stretches back to Thomond Park last St Stephen’s Day.
The loss of light was a fitting intrusion, an unexpected bolt on a night that promised little but one that had already morphed into an electric evening thanks to the have-a-go willingness of a visiting side that had little or nothing to play for.
Ultimately, it changed little, given Leinster’s home semi-final berth had already been secured.
Leo Cullen made 13 changes to the side that started the Champions Cup loss to Clermont Auvergne in Lyon and more alterations were required, as Tom Daly lost seven minutes to a head injury assessment and Dominic Ryan disappeared down the tunnel with an arm injury.
Ryan’s departure was hugely unfortunate for the flanker who has yet to secure a roster spot anywhere next year, but he had at least crossed over for the first try a couple of minutes before being forced off. It was a decent move, full of invention and pace. Ryan ran the perfect seam to go under the posts once Zane Kirchner had burst the cover and scooped an unselfish pass back off his shoulder when he could have run for the chalk himself.
Rory O’Loughlin pounced for a second inside the first 10 minutes, the centre profiting from a kind bounce, when none of Adam Byrne nor the Glasgow pair of Tommy Seymour or Lee Jones could collect a dropping bomb.
The visitors needed five points from their last two games and a ridiculous run of results elsewhere if a semi-final slot was to open up for them and, with Gregor Townsend punching in for duties with the Scotland side in a matter of weeks, they could have folded early.
Instead, they came to play a bit of rugby and they showed enough of the attractive, running game for which they became renowned under Townsend as they pushed deep into Leinster territory.
Reward was limited initially. Two Peter Horne penalties was all they managed in the first-half, while Leinster struck for a third try five minutes from the break, with loosehead Peter Dooley flopping down off the back of a maul that started with a lineout inside the 22.
A Ross Byrne penalty left it 23-6 at the break. So far, so routine.
The Warriors had butchered a few openings in the first period, but they were much more clinical on the restart, with tries after 46 and 65 minutes — both of them converted — sandwiching a Horne penalty and a Kirchner try for the hosts. All of which left the gap at just five points with a dozen minutes to go. When Finn Russell pirouetted over to the left of the posts for a third Glasgow try, which he would convert, it left Glasgow two points to the good down the final stretch.
A first PRO12 loss at the RDS since February of 2015 — and only a second since March of 2013 — beckoned until Joey Carbery came off the bench to land a penalty that reclaimed the lead and, after a spell in the dark, all five points.
Last night also saw Cardiff Blue beat Zebre 30-24 and Edinburgh beat Newport Gwent Dragons 24-20.
Z Kirchner; A Byrne, R O’Loughlin, T Daly, F McFadden; R Byrne, N McCarthy; P Dooley, J Tracy, M Ross; R Molony, M Kearney; D Ryan, J van der Flier, D Leavy.
N Reid for Daly (4-11 and 54); P Timmins for Ryan (8); M Bent for Ross (54); J McGrath for Dooley (57); I Nagle for Kearney and J Gibson-Park for McCarthy (both 67); J Carbery for R Byrne (71); R Strauss for van der Flier (79).
T Seymour; L Sarto, N Grigg, S Johnson, L Jones; P Horne, H Pyrgos; A Allan, F Brown, S Puafisi; B Alainu’uese, J Gray; T Swinson, C Fusaro, A Ashe.
Z Ferguson for Puafisi and R Harley for Alainu’uese (both 37); P MacArthur for Brown, G Reid for Allan and A Price for Pyrgos (all 54); F Russell for Horne (54); A Dunbar for Grigg and M Fagerson for Ashe (both 61).
M Mitrea (FIR).