Leinster made sure of a place in the last eight of the Heineken Cup with a bruising win away to Glasgow.
The home side made most of the running in the first half but only had two Duncan Weir penalties to show for their efforts, with the game tied at 6-6.
After the interval, Rob Kearney grabbed a try for the defending champions, with Colin Gregor replying for the hosts.
Issac Boss powered over for the decisive score late in the game to end Glasgow's hopes of qualification.
Leinster were far from their best and, having lost Sean O'Brien to a yellow card for the final five minutes, had to defend like lions to close out their victory.
Glasgow will be frustrated after squandering a number of good opportunities but lacked composure and an inventive spark in the opposition 22.
Sean Lineen's side were spirited throughout and Leinster were rattled in the opening exchanges, failing to find their range on the tight Firhill pitch.
Glasgow Warriors: Lamont, Seymour, Hogg, Morrison, Shaw, Weir, Cusiter, Welsh, MacArthur, Kalman, Gray, Kellock, Harley, Fusaro, Barclay. Replacements: Nathan for Shaw (62), Wight for Weir (74), Gregor for Cusiter (59), Hall for MacArthur (56), Ryder for Gray (61), Beattie for Barclay (61). Not Used: Reid, R. Grant.
Leinster: R. Kearney, D. Kearney, McFadden, D'Arcy, Nacewa, J. Sexton, Reddan, Healy, Cronin, Ross, Cullen, Toner, O'Brien, Jennings, Heaslip. Replacements: O'Malley for D. Kearney (64), Boss for Reddan (59), van der Merwe for Healy (64), White for Ross (66), Browne for Cullen (74), R. Ruddock for Jennings (59). Not Used: Dundon, Madigan.
Att: 6,479
Ref: Nigel Owens (Wales)