Ulster fly-half Paddy Jackson kicked six unanswered penalties in the second half to give the Irish side an 18-12 win over the Ospreys in Swansea.
It was a tale of two kickers at the Liberty Stadium, where the magnificent Jackson booted Ulster to a superb away win.
Dan Biggar was equally prolific for the former champions, landing four kicks of his own. The Ospreys led throughout the early stages of this bruising encounter, but fell victim to a ferocious second half onslaught from the Irish visitors.
It was the Welsh kingpins who made the superior start, and the hosts were assisted by early Ulster indiscipline.
A very experienced and physical Osprey pack, including Lions captain Alun Wyn Jones making his 150th appearance for the club, made initial inroads; with big forwards driving intently at the Ulster defence.
But the visitors weathered the early storm and settled well, and responded with some decent continuity of their own that witnessed big ball carriers like Nick Williams and Chris Henry testing the defence of the Welsh region.
The Irish province's cause was not helped by the withdrawal of fullback Craig Gilroy before the 15-minute mark. The Ospreys looked the livelier of the sides; with new signing Tito Tebaldi particularly impressive.
Consequently it was the home side that secured the first points of the evening when fly-half Biggar slotted a penalty on 20 minutes. The game descended into a rather turgid spectacle thereafter; with both sides struggling to inject any fluidity into their game.
This phase of the game was characterised by a succession of handing errors and spilled balls.
But it was the Ospreys who seemed in control of proceedings, and Biggar extended the lead on the cusp of half time when he nailed a superb penalty to make it 6-0. By the end of the half, therefore, the pacesetting Welshmen were undeniably worth their lead.
The second half started in a similar vein. Paddy Jackson tried to launch his side downfield with a purposeful kick on 41 minutes, but winger Michael Allen was caught offside. The metronomic Biggar made no mistake with the ensuing penalty.
At 9-0, the hosts were dominating the match, and Ulster had left themselves a mountain to climb against the in-form Welsh side.
The Ospreys' number ten punished the Irishmen further three minutes later when he converted another penalty to earn his team a 12-point advantage. Jackson clawed back the arrears on 48 minutes when he landed a well -taken kick.
Gradually Ulster were regaining a tenuous foothold in the game, and Irish international Jackson narrowed the gap further on 51 minutes to make it 12-6.
At last, the visitors' pack began to give them a platform, and Ulster's scrum secured another penalty attempt on 56 minutes. Jackson maintained his accomplished kicking display to bring the Ulstermen within three points.
Their retinue of substitutes galvanised the visitors further, and they were rewarded for a patient build up when Jackson levelled the scoreline at 12-12 on 64 minutes.
The youngster followed that up on 72 minutes when he gave his team an improbable lead considering Ulster's lethargic start to the game.
Replacement prop Aaron Jarvis handed the match to the Irishmen on 76 minutes when he gave away a costly penalty, and was sin-binned for his misdemeanour. Jackson sealed the win with another well-struck penalty to make it 12-18.
The Ospreys desperately tried to salvage the game in the final minutes, and laid siege to the Ulster line with breathtaking intensity - but Ulster clung on to achieve an excellent victory.
This win was just reward for a vastly improved second half performance from the Ravenhill men. The Belfast team will now enter the Heineken Cup with renewed confidence. For a chastened Ospreys, however, this will be viewed as the one that got away.
Pens: Biggar 4
Yellow Card: Jarvis
Pens: Jackson 6
Yellow Card: Olding
Ospreys: 15 Richard Fussell, 14 Jeff Hassler, 13 Andrew Bishop, 12 Ashley Beck, 11 Eli Walker, 10 Dan Biggar, 9 Tito Tebaldi, 8 Joe Bearman, 7 Justin Tipuric, 6 Tyler Ardron, 5 Ian Evans, 4 Alun Wyn Jones (c), 3 Adam Jones, 2 Richard Hibbard, 1 Ryan Bevington.
Replacements: 16 Scott Baldwin, 17 Duncan Jones, 18 Aaron Jarvis, 19 James King, 20 Sam Lewis, 21 Tom Habberfield, 22 Matthew Morgan, 23 Ben John.
Ulster: 15 Craig Gilroy, 14 Andrew Trimble, 13 Jared Payne, 12 Luke Marshall, 11 Michael Allen, 10 Paddy Jackson, 9 Paul Marshall, 8 Nick Williams, 7 Chris Henry, 6 Robbie Diack, 5 Dan Tuohy, 4 Johann Muller, 3 Declan Fitzpatrick, 2 R Best (c), 1 Tom Court.
Replacements: 16 Rob Herring, 17 Callum Black, 18 Bronson Ross, 19 Iain Henderson, 20 Roger Wilson, 21 Michael Heaney, 22 Stuart Olding, 23 Darren Cave.
Referee: Peter Fitzgibbon (Ireland)
Assistant referees : Jon Mason (Wales) and Wayne Davies(Wales)
TMO: Derek Bevan (Wales)
by Rory McGimpsey