Glasgow had Dan Parks' boot to thank as they narrowly defeated Magners League champions Leinster 15-12 at Firhill Stadium on Friday.
Scotland fly-half Parks produced a near-flawless kicking display in difficult conditions, converting five of his six penalty attempts to win his tee battle with Felipe Contepomi.
The Puma was successful with four of his five but it was not enough to halt Leinster's travel sickness in the defence of their title.
The Irish side have looked imperious in the Heineken Cup but found themselves leapfrogged by their opponents in the Magners League table after this game.
It could have been worse than a bonus-point defeat for the visitors, with the Warriors seeing a first-half try from Max Evans controversially disallowed.
Glasgow were forced into one change from the starting XV named in midweek, Eric Milligan replacing Dougie Hall at hooker. Hall's shoulder injury was not expected to prevent him linking up with the Scotland camp next week.
Ireland full-back Girvan Dempsey recovered from illness to start for Leinster, who were already missing talismanic centre Brian O'Driscoll.
And it took less than a minute for the visitors to infringe at the breakdown, Parks converting the penalty from in front of the posts.
But Glasgow soon reciprocated, allowing Contepomi to level.
The Warriors thought they had scored the opening try when Evans combined with Lome Fa'atau down the right before crossing, but the officials had spotted a forward pass.
Glasgow soon had the consolation of another successful Parks penalty after foul play at a lineout. But neither kicker was taking any chances in the wind, with both opting to blast their penalty shots.
The hosts were on top but had a scare when Contepomi broke through down the right and was scuppered only by a lack of support.
A superb 40-metre penalty then gave the home side a deserved six-point cushion. That became nine minutes later from in front of the posts, the referee sin-binning Jamie Heaslip in the process.
The fourteen men wasted a chance to cut the deficit immediately when Contepomi missed a penalty and Glasgow went into the break 12-3 up.
Glasgow withdrew captain Alastair Kellock and prop Ed Kalman at the interval for Tim Barker and Moray Low.
Then Contepomi atoned for his earlier penalty miss shortly after the restart as Leinster closed to within a converted try of their opponents.
With the wind now on his back, the Argentinean booted another from near halfway to make it 12-9 with more than a quarter of the match remaining.
Leinster continued to be dogged by ill-discipline and Parks made them pay with another penalty, but Glasgow opened the door again and Contepomi made no mistake with his own kick.
With time running out, Parks missed a tough touchline penalty to calm the nerves of the Firhill faithful. But it did not matter as Glasgow held on for the points.
Pen: Parks 5
Pen: Contepomi 4
Glasgow: 15 Bernardo Stortoni, 14 Lome Fa'atau, 13 Max Evans, 12 Graeme Morrison, 11 Thom Evans, 10 Dan Parks, 9 Mark McMillan, 8 Johnnie Beattie, 7 John Barclay, 6 Kelly Brown, 5 Alastair Kellock (c), 4 Dan Turner, 3 Ed Kalman, 2 Dougie Hall, 1 Kevin Tkachuk.
Substitutes (From): Pat McArthur, Moray Low, Tim Barker, Stevie Swindall, Richie Vernon, Colin Gregor, Ruaridh Jackson, Andrew Henderson, Hefin O'Hare.
Leinster: 15 Girvan Dempsey, 14 Shane Horgan, 13 Luke Fitzgerald, 12 Felipe Contepomi, 11 Rob Kearney, 10 Jonathan Sexton, 9 Chris Whitaker (c), 8 Jamie Heaslip, 7 Shane Jennings, 6 Rocky Elsom, 5 Malcolm O'Kelly, 4 Devin Toner, 3 Stan Wright, 2 John Fogarty, 1 Cian Healy
Replacements: (From) Brian Blaney, CJ van der Linde, Trevor Hogan, Stephen Keogh, Sean O'Brien, Chris Keane, Gary Brown, Simon Keogh
Referee: Gwyn Morris (Wales)
Touch judges: Rob Dickson (Scotland), David Anderson (Scotland)