Ulster booked their place in Heineken Cup quarter-finals on Friday thanks to a 23-6 win over Glasgow at a rain-lashed Ravenhill on Friday.
The result means Ulster became the first team to qualify for the play-offs by topping Pool Four in nail-biting circumstances.
The bonus point may have eluded last year's beaten finalists, but given the magnificent way in which Glasgow rallied in the opening quarter of the second half, Ulster were mightily relieved to even have achieved victory. This was a pulsating and riveting encounter in the best traditions of the competition, and produced breathtaking entertainment that belied the appalling conditions.
It was an error-strewn opening to the game, as the inclement weather threatened to ruin a hotly-anticipated encounter. The opening minutes were characterised by handling errors and both sets of players struggled to cope with the conditions.
Indeed the start of the match was blighted by a succession of knock-ons. It was clear that Ulster intended to use their devastating scrum as an attacking weapon. It was a surprise, therefore, when Glasgow were awarded an early penalty for Ulster collapsing the scrum. Subsequent replays revealed that Ulster tight-head John Afoa had slipped, however.
Normal service was resumed thereafter, with the Ulster eight turning the screw on their Scottish opponents. Pienaar opened the scoring with a well taken penalty on six minutes, to give the hosts a 6-0 lead.
The conditions, meanwhile, were deteriorating rapidly as the handing became a lottery. Good possession and protection of the football, therefore, became paramount. Slowly but surely, Ulster were beginning to grind down the Warriors and played a smart territorial game through the boot of Pienaar and his half-back colleague, Paddy Jackson.
This intense pressure produced an inevitable breakthrough as Nick Williams bulldozed over on 20 minutes. It is difficult to conceive of a more certain try, but the referee eccentrically referred to the TMO. Pienaar converted to m make it 10-0 to the Ulstermen.
Ulster were displaying sublime tactical kicking in the conditions, keeping Glasgow imprisoned in their own half. The visitors did have their opportunities to strike back, and secured better possession at the tail end of the half. They did earn their reward by winning two eminently kickable penalties, but Duncan Weir pushed wide on both occasions.
If those misses constituted a let off for Ulster, Weir did make amends on 48 minutes when he opened the visitors' account to cut Ulster's advantage to 10-3.
Gregor Townsend must have given his troops an almighty rollicking at half-time, as the Warriors were unrecognisable for much of the second half. The visitors began to secure better field-position, utilising their rolling maul to devastating effect.
The Glasgow forwards reverted to keeping the ball up their jumper, playing the conditions superbly. Ulster seemed shell-shocked at the increase in intensity, and the anxiety in Ravennhill became palpable when Weir pegged the hosts back to 10-6.
When Iain Henderson was sin-binned for failing to roll away, Ulster's qualification hopes seemed in real jeopardy. Ulster were losing control. The introduction of substitutes, Paul Marshall and Roger Wilson steadied the ship.
Ulster were now achieving better possession, and fought hard to close out the game. Pienaar did extend the gap on 62 minutes to give some breathing space.
Payne secured the victory on 73 minutes, making it 18-6 to the hosts. More than anything, this passage personified the spirit and composure in this team.
Ostensibly Ulster were focusing on safeguarding the win, but the bonus point was definitely on their minds. They came close to achieving that when Cave touched down on 78 minutes. But they couldn't quite get there.
A superb victory in the end, but quarter final qualification was the prize that Ulster coveted most.
Tries: Williams, Payne, Cave
Pens: Pienaar 2
Yellow card: Henderson
Pens: Weir 2
Ulster: 15 Jared Payne, 14 Andrew Trimble, 13 Darren Cave, 12 Paddy Wallace, 11 Craig Gilroy, 10 Paddy Jackson, 9 Ruan Pienaar, 8 Nick Williams, 7 Chris Henry (c), 6 Robbie Diack, 5 Iain Henderson, 4 Louis Stevenson, 3 John Afoa, 2 Rory Best, 1 Tom Court.
Replacements: 16 Rob Herring, 17 Calum Black, 18 Declan Fitzpatrick, 19 Neil McComb, 20 Roger Wilson, 21 Paul Marshall, 22 Michael Allen, 23 Chris Cochrane.
Glasgow: 15 Peter Murchie, 14 Sean Maitland, 13 Alex Dunbar, 12 Peter Horne, 11 DTH van der Merwe, 10 Duncan Weir, 9 Henry Pyrgos, 8 Josh Strauss, 7 Robert Harley, 6 James Eddie, 5 Al Kellock (c), 4 Tom Ryder, 3 Moray Low, 2 Doug Hall, 1 Ryan Grant.
Replacements: 16 Pat MacArthur, 17 Gordon Reid, 18 tbc, 19 Nick Campbell, 20 Tim Swinson, 21 Nikola Matawalu, 22 Scott Wight, 23 Stuart Hogg.
Referee: Pascal Gauzere (France)
Assistant referees: Laurent Cardona (France), StÃ©phane PomarÃ¨de (France)
Television match official: HervÃ© Dubes (France)
Timekeeper: David Armstrong (Ireland)
Citing commissioner: Peter Larter (England)
Assessor: Tom Aplin (Ireland)
By Rory McGimpsey