Leinster claimed a vital Heineken Cup victory on the road on Saturday with a 19-9 win over the Ospreys at Liberty Stadium.
It was far from pretty, but the three-time champions got the job done, scoring the only try of the game through flanker Sean O'Brien and shutting the home side down with an impressive defensive display.
Points were at a premium, especially in the second-half as Leinster's Jimmy Gopperth and the Ospreys' Dan Biggar traded a penalty each, as the Irish side repeatedly shut down the hosts' attacks.
A battle between British and Irish Lions back-rowers Justin Tipuric and O'Brien at the breakdown was in the end comfortably edged out by the Irishman, who scooped a Man of the Match award for his troubles.
Gopperth won the starting spot at fly-half for Leinster ahead of Ian Madigan and kicked exceptionally in the Liberty Stadium on his Heineken Cup debut, landing one conversion and four penalties to keep the scoreboard ticking over in the first-half.
Early scrum dominance from the Ospreys put them into a 6-0 lead after Biggar struck two penalties, lifting the home crowd as the Welsh outfit aspired to reach the quarter-final stage of the competition for the first time since 2009-2010.
Biggar continued his impressive early season form as he scored the opening points of the match two minutes in after some dogged work by the fit-again Ryan Jones.
But a shift in momentum at the scrum, partly inspired by the substitution of Ireland tighthead Mike Ross for replacement Martin Moore early in the first half, saw the men in blue begin to control that area of the set-piece to give Gopperth opportunities for territory and points.
The Kiwi fly-half had already added three points to the board before Leinster scored the game's only try.
Sean Cronin was industrious throughout but he picked a sharp line through the Ospreys tacklers near the left touchline, beating one man and spinning out of another tackle before offloading to O'Brien for the try.
With Gopperth making no mistakes with the conversion from wide out on the touchline, Leinster flipped a six-point deficit into a 10-6 lead.
After Gopperth's second penalty had them seven points ahead at half-time, the Ospreys were left chasing the game - but for all of their best efforts lacked the accuracy at key moments to make Leinster pay.
Gopperth and Rob Kearney's cultured boots continued to press the Ospreys back into their own 22 on an increasingly frustrating night for the Swansea faithful.
They continued to look for the all important try to get back on terms and Canadian winger Jeff Hassler looked destined for the try-line as he broke free on the right wing but he was halted on Leinster's 22 by the impressive Gopperth.
It leaves the Ospreys desperate to take something from Franklin's Gardens next weekend to keep their hopes alive, whilst Leinster host French champions Castres.
Pens: Biggar 3
Pens: Gopperth 4
Ospreys: 15 Richard Fussell, 14 Ben John, 13 Andrew Bishop, 12 Ashley Beck, 11 Eli Walker, 10 Dan Biggar, 9 Tito Tebaldi, 8 Joe Bearman, 7 Justin Tipuric, 6 Ryan Jones, 5 James King, 4 Alun Wyn Jones (capt), 3 Adam Jones, 2 Richard Hibbard, 1 Duncan Jones.
Replacements: 16 Scott Baldwin, 17 Ryan Bevington, 18 Aaron Jarvis, 19 Tyler Ardron, 20 Sam Lewis, 21 Tom Habberfield, 22 Matthew Morgan, 23 Jeff Hassler.
Leinster: 15 Rob Kearney, 14 Fergus McFadden, 13 Brendan Macken, 12 Gordon D'Arcy, 11 Dave Kearney, 10 Jimmy Gopperth, 9 Isaac Boss, 8 Jamie Heaslip (capt), 7 Sean O'Brien, 6 Kevin McLaughlin, 5 Mike McCarthy, 4 Devin Toner, 3 Mike Ross, 2 Sean Cronin, 1 Cian Healy.
Replacements: 16 Aaron Dundon, 17 Jack McGrath, 18 Martin Moore, 19 Quinn Roux, 20 Rhys Ruddock, 21 Eoin Reddan, 22 Ian Madigan, 23 Luke Fitzgerald.
Venue: Liberty Stadium
Referee: Wayne Barnes (England)
Assistant referees: Roger Whitfield (England), Paul Dix (England)
Television match official: Geoff Warren (England)
Timekeeper: David Hudson (England)