NOT quite the Sunday roast many expected, but the champions duly claimed their berth in the Heineken Cup knockout stages, with the prospect of a Lansdowne Road quarter-final if they take care of Montpellier next weekend.
They had to scrap for it all the way, though.
Firhill is an austere outpost on the European rugby circuit, the home of Partick Thistle FC, nestling amid a cordon of concrete tower blocks, and the no-frills surroundings were ideally suited to a contest which bristled with intensity but was always more grunt than guile.
It was classic away-day, get the job done stuff by Leinster, a mile away from the joyous destruction of Bath in Lansdowne Road last month but wholly meritorious nonetheless, and coach Joe Schmidt was entitled to give off an air of quiet satisfaction afterwards.
These are the type of wins that stand to a team.
Glasgow may have lacked invention in attack but they were not wanting for commitment in defence and Sean Lineen's brand of keep-it-simple rugby had them well in the contest and pushing for a draw up until the final whistle.
Indeed, if Stuart Hogg had made allowance for the two men outside him instead of cutting back into contact on 72 minutes, Glasgow would have got the try they needed to push on for a shock victory but Leinster, even after losing Sean O'Brien to the bin with five minutes left, showed commendable resolve to keep the home side out.
Jonathan Sexton played on one leg for a large chunk of the game, having rolled his ankle after half an hour, but the out-half stuck to his task admirably, executing a superb cross-field kick for the crucial Rob Kearney try just after half-time when Glasgow were left to rue their momentary hesitancy.
While Leinster's back-row had their hands full throughout, Leo Cullen led from the front in the second-row, with Cian Healy and Sean Cronin both prominent as regular ball-carriers.
Cronin had a very good all-round game, accurate with his line-out throwing and the one player to consistently hit the ball from depth on a day when a lot of Leinster's carries were too lateral and static.
Fergus McFadden looked sharp in midfield and, after Sexton's injury, took over the kicking duties with his usual level of accuracy.
He was also centrally involved in the best Leinster move of the match in the second half when quality line-out ball gave O'Brien a rare taste of open ground before good work by Gordon D'Arcy brought McFadden right to the Glasgow line.
The bench also played a significant role, Damian Browne, Heinke van der Merwe and, particularly, scrum-half Isaac Boss injecting extra physicality and vigour to proceedings.
Boss did much to stifle Glasgow's late insurgency with his fringe tackling and also struck for the second try after the home side had brought it back to 16-16 through sub Colin Gregor.
It was good work from O'Brien turning over Johnny Beattie that provided the opportunity, and Boss is a hard man to stop from close range.
That made it 23-16 with just over 10 minutes to go, when the visitors went into lockdown mode.
They are grateful for any spark of positivity in these parts and, while the record Heineken Cup Firhill crowd of 6,479 seems paltry by Irish provincial standards, it was riotously acclaimed here.
For a success-starved rugby region such as this, the home side were also happy to re-emerge for a semi-lap of honour based on giving the European champions a proper contest.
You suspect it might not have been quite so close if Leinster had got their tactics right in the first half. Prompted by an excellent, Phil Bennett-esque Sexton break from the kick-off, which took play deep into Glasgow territory, Leinster opted to keep ball in hand when kicking for territory seemed the better option, given the softening-up prerogatives.
Glasgow met the Leinster runners head-on and, as their robust defence continued to drive Leinster back on their haunches (O'Brien taking a massive early hit), confidence and self-belief flowed into the home players.
Their own attacks were never going to ask too complicated questions but Leinster's defence was assured, Healy and Isa Nacewa making some big hits, and 6-6 at half-time was a fair enough reflection of what had taken place.
Schmidt obviously got his message across during the break because there was a discernible change in approach as Sexton immediately began to play more of a territory game, complemented by better depth from their runners.
Leinster will bank on Sexton's ankle clearing up quickly and having Luke Fitzgerald and Richardt Strauss available for next weekend and, for a team that has successfully employed distinctive away and home policies under Schmidt, it is safe to expect an attacking expansion next weekend.
This was not a victory that will be treasured in years to come but, in its own way, it was a win that was characteristic of a side that knows how to maintain momentum.
A decent result with plenty of areas to work on and keep minds focused during the week -- bad news for Montpellier.
GLASGOW WARRIORS -- R Lamont; T Seymour, S Hogg, G Morrison, C Shaw (T Nathan 67); D Weir (S Wright 73), C Cusiter (C Gregor 58); J Welsh, P MacArthur (D Hall 56), E Kalman (G Reid 69); R Gray (T Ryder 60), A Kellock (capt, T Ryder 31-40), R Harley, C Fusaro, J Barclay (J Beattie 60).
LEINSTER -- R Kearney; D Kearney (E O'Malley 63), F McFadden, G D'Arcy, I Nacewa; J Sexton, E Reddan (I Boss 58); C Healy (H van der Merwe 63) , S Cronin, M Ross (N White 65); L Cullen (capt, D Browne 73), D Toner; S O'Brien, S Jennings (R Ruddock 58), J Heaslip. Yellow card: O'Brien 75.
REF -- N Owens (Wales).