South Africa scrum-half Ruan Pienaar scored all of Ulster's points in a bruising but glorious 22-19 win over Leicester at Welford Road.
A second-half try from Niall Morris had given Leicester a ten-point cushion before Ruan Pienaar dragged his side back into the contest by charging down Toby Flood to level things up, before Pienaar's boot settled the struggle.
It means that Ulster finish as the top seeds in the competition with 26 points from 30, six wins from six - a fantastic record considering their pool.
This was an utterly absorbing collision between two physical teams who scrapped and battled, legally and illegally, for supremacy in a straight shootout to top Pool 5.
Ulster's previous record in the competition leaves them trailing in the wake of their Irish sisters Munster and Leinster in terms of trophies won, but they do possess ample talent and resolve.
This was a test of their character and a chance to earn plenty of respect - Leicester may not have been at their strongest but they do not lose at home in Europe, the last time coming in 2007.
To come from ten points down at Welford Road of all places was a massive statement of intent ahead of the knockout stages.
Flood opened Leicester's account after Marcos Ayerza got the better of John Afoa at the opening scrum, two world class props worth their weight in gold going at it in just one of a multitude of high quality matchups.
With the wind at his back Flood added a second penalty before Ulster's first points, a fine kick from Ruan Pienaar giving Ulster field position and a maul from the visitors culminating in a penalty for the Springbok to slot over.
Jordan Crane departed due to a knock but his replacement Steve Mafi won the following lineout that set Graham Kitchener galloping towards the Ulster line, only last ditch defence keeping him out. Leicester left with another penalty though to stretch their lead to 9-3.
The Premiership champions' most potent weapon early on might have been the scrum, but the Ulster maul grew into the match and created Pienaar's second penalty attempt.
That power transferred to the breakdown as Nick Williams rose to the fore and won the visitors another penalty, which Pienaar converted with an outstanding long-range strike from just over the halfway line.
The bounce of the ball nearly handed Andrew Trimble an opportunistic score chasing Pienaar's chip kick, but his foot betrayed him, grazing the touchline. Mat Tait was the second Tiger to need to be replaced as the warfare took its toll, while Paddy Jackson nearly took three points for himself, but his drop goal flew wide.
Chris Henry's eagerness to get away from the scrum cost him as Flood landed his fourth kick of the night, the Tigers going back ahead with tension mounting in the second half.
Such was the intensity of both defences that it took a rare break for either to find the try line, and Morris pounced.
Chasing Flood's gem of a grubber kick into the corner, the Irishman was tackled early by Jackson but it didn't matter as Morris did enough to put downward pressure on the ball as he went over. A ten-point advantage in games such as these, such as Leicester possessed at 19-9, is almost priceless.
The bouncing ball may have benefited Morris but it spun Scott Hamilton inside out, Tait's replacement eluded by a high kick that left Ulster attacking in the Tigers 22, but the Leicester defence was ironclad and came out on top after 19 phases.
Ulster did get three points shortly after through a Pienaar penalty, cutting the deficit to seven entering the final quarter. He wasn't quite done though.
Spotted bursting towards Flood in the Leicester 22, the scrum-half charged down the England fly-half's clearance and had the speed and fortune to touch down - Ulster's biggest player making a big play when it mattered and adding the conversion to boot.
Now a question of patience and fitness, Pienaar came again with more composure to put Ulster ahead for the first time in the match on 69 minutes with his fifth penalty.
Flood's last throw of the dice though was a good one, a perfectly placed kick into the corner to provide the Tigers pack with a platform. It was Flood however who spilled the ball, Rory Best of all the possible kickers clearing long; no doubt to the relief of his team-mates.
Luke Marshall's kick into the corner was so difficult to call in bouncing over the corner flag that it required the advice of the TMO, the difference between a five-metre lineout and a scrum back in Ulster's half being monumental.
The stage seemed set for a Tigers scrum penalty to clinch the draw or better, but it was Ulster's front-row that rose on top to clear their lines.
There was (of course) time for one more Leicester scrum with time up on the clock as the Tigers scrambled from side to side looking for a chink in the Ulster armour, but their seven-year undefeated streak at Welford Road came to an end. This was Ulster's night - unbeaten Ulster's night - and they were more than worthy of the glory.
Pens: Flood 4
Pens: Pienaar 5
Leicester Tigers: 15 Mathew Tait, 14 Niall Morris, 13 Matt Smith, 12 Anthony Allen, 11 Vereniki Goneva, 10 Toby Flood (c), 9 Ben Youngs, 8 Jordan Crane, 7 Julian Salvi, 6 Jamie Gibson, 5 Graham Kitchener, 4 Ed Slater, 3 Dan Cole, 2 Tom Youngs, 1 Marcos Ayerza.
Replacements: 16 Rob Hawkins, 17 Boris Stankovich, 18 Fraser Balmain, 19 Louis Deacon, 20 Steve Mafi, 21 David MÃ©lÃ©, 22 Owen Williams, 23 Scott Hamilton.
Ulster: 15 Jared Payne, 14 Andrew Trimble, 13 Darren Cave, 12 Luke Marshall, 11 Craig Gilroy, 10 Paddy Jackson, 9 Ruan Pienaar, 8 Nick Williams, 7 Chris Henry, 6 Roger Wilson, 5 Dan Tuohy, 4 Johann Muller (capt), 3 John Afoa, 2 Rory Best, 1 Callum Black.
Replacements: 16 Rob Herring, 17 Tom Court, 18 Ricky Lutton, 19 Iain Henderson, 20 Robbie Diack, 21 Paul Marshall, 22 David McIlwaine, 23 Michael Allen.
Referee: Nigel Owens (Wales)
Assistant referees: Sean Brickell (Wales), Jonathan Mason (Wales)
Television match official: Tim Hayes (Wales)
by Ben Coles