Leinster emerged winners from a bruising encounter at Scotstoun to halt a run of successes by Glasgow in the Pro12 with a doggedly defensive performance in wet conditions that was made easier by two sin-binnings for the Warriors.
Crucially for Leinster's future prospects, and more so those of Ireland, back Sean O'Brien came through his comeback match with aplomb. The Leinster No 8 carried ball well and featured in the move that led to his side's second and decisive penalty goal early in the second half.
In a match that featured second-string players on both sides, it was experience that ultimately counted in the end. And no more so than at full-back where Isa Nacewa, also making a return, was the saviour of Leinster on numerous occasions with quick decision-making in defence and security under the high ball.
But it was Ian Madigan, making his 60th appearance for Leinster, who was the match winner, the out-half succeeding with two penalty kicks at goal from three attempts, eclipsing the efforts of his opposite numbers Peter Horne and Scott Wight.
After dominating territory for the opening minutes Leinster reaped points with a penalty from Madigan, but it merely evinced a massive attacking effort from Glasgow.
But after Leinster were put in difficulty in their own '22' from a charged down kick, a break by scrum-half Isaac Boss switched pressure back on to the home side, increased with a penalty kick to the corner by Madigan, allowing the visitors to launch a series of short-range drives close to the Warriors' line.
No try ensued and when Leinster were given a second chance from a another penalty kick to the corner, Glasgow were able to steal the ball to thwart a potential score only for the Warriors to give away a free-kick. But once again Glasgow disrupted their opponents' attacking intentions.
A yellow card dished out to Glasgow lock Tom Ryder gave Madigan a second kick at goal, but this time the ball was wide of the posts. Another chance presented itself when Nacewa burst through midfield only to be caught by DTH van der Merwe.
Then when Leinster mounted another series of drives by their powerful forwards deep inside the Warriors' '22', a try seemed inevitable but a penalty against Shane Jennings gave Glasgow the relief they needed. At the subsequent line-out Quinn Roux suffered a shoulder injury and was replaced by Devin Toner.
The game opened up in the final few minutes of the first half, but it was defence that ruled the day leaving Leinster disappointed as they trooped into the interval break with a paltry three-point lead that barely reflected their territorial dominance.
It was Glasgow who came out of the blocks faster at the beginning of the second half but Leinster claimed the first points with a second penalty from Madigan following the sin-binning of Warriors skipper Chris Fusaro.
Glasgow had a chance to reply but centre Peter Horne was wide with his penalty kick and then minutes later completely fluffed a shot at goal. Then when replacement out-half Scott Wight kicked at goal, the ball was inches outside the near upright.
The Warriors cranked up the pressure in the closing stages but accurate defence by Leinster ensured that Glasgow made little progress resulting in a hard-earned, if not pretty, victory for the Irish province.
Glasgow Warriors – P Murchie; T Seymour (B McGuigan 53), A Dunbar, P Horne, DTH Van Der Merwe; R Jackson (S Wight 56), S Kennedy; O Fainga'anuku (G Hunter 39 (M Low 60)), P MacArthur (F Gillies 74), M Cusack (M Low ), T Swinson, T Ryder, R Harley, C Fusaro (R Wilson 59), J Strauss (J Eddie 68)
Leinster – Isa Nacewa; D Kearney, B Macken, A Goodman, F Carr; I Madigan, I Boss; J McGrath (J O'Connell 64), A Dundon (T Sexton 61), J Hagan (M Moore 67), L Cullen, Q Roux (D Toner 32), K McLaughlin, S Jennings, S O'Brien.
Ref –N Hennessey (WRU).