Home team's 35 phases fall short
Saracens secured a second successive European Cup semifinal spot in dramatic fashion on Saturday.
They saw off a heroic effort from 14-man Ulster at a raucous Ravenhill - winning 17-15.
Jared Payne's fifth-minute red card left the odds stacked in Saracens' favour, but Ulster's never-say-die attitude ensured they remained in the hunt until the very end of another pulsating encounter.
Chris Ashton scored a try in either half for the English league leaders and Mouritz Botha also crossed the Ulster line.
However, Owen Farrell was off colour from the tee and Ulster nearly made him pay - as Paddy Jackson added two late penalties to a hat-trick of first-half strikes from Ruan Pienaar.
Ulster kept possession in Saracens' territory for 35 phases as they went in search of a fairytale ending, with the clock deep into the red. However, Sarries' famed 'Wolf Pack' defence kept their composure to set up a final-four clash with ASM Clermont Auvergne at Twickenham on Saturday, April 26.
Farrell surprisingly missed the chance to give his side an early lead when he pulled a relatively straightforward shot at goal wide of the left post with less than three minutes gone but the game took a significant swing in their favour when Payne was dismissed 90 seconds later.
The Ulster fullback collided with his opposite number Alex Goode when challenging for Jackson's up and under, with the end result a nightmare one for both men.
Goode was stretchered off after landing on his head and Payne was given his marching orders by referee Jerome Garces after a lengthy consultation with the TMO.
Tommy Bowe's opportunistic break showed Ulster had no intention of rolling over but things went from bad to worse for the Northern Irishmen when veteran hooker Rory Best limped off with an ankle injury with 12 minutes on the clock.
Saracens had already been forced into a second backline reshuffle when Charlie Hodgson came on at flyhalf and Farrell moved into the midfield, after Duncan Taylor was forced off but the loss of Best threatened to hit Ulster even harder given his importance to the province.
But it was the home side who opened the scoring when Pienaar drilled a long-range penalty through the posts with a quarter of an hour played and they could have been six points to the good two minutes later had the Springbok star not failed with a 50-metre attempt after Billy Vunipola had been penalised at line-out time.
It took Sarries 22 minutes to make their one-man advantage pay but the first try of the night was well worth the wait.
The Saracens pack provided the platform with a strong shove at a scrum on halfway, with Hodgson holding two defenders to pick up Ashton's inside line. The England wing held his depth perfectly before changing tact from inside to out to see off the desperate diving challenge of Luke Marshall on his way to his eighth try of the European campaign.
Farrell's conversion attempt from close to the 15-metre line on the right-hand side went the same way as his early penalty, though, and Ulster were back in front on the half hour as Pienaar slotted his second shot at goal.
The influential South African failed with another penalty attempt after 37 minutes, but he was on target again on the stroke of half-time to give Ulster a shock 9-5 lead at the break.
Sarries edged back in front when Schalk Brits' powerful burst was followed by patient phase play and continuous quick ball that eventually allowed Mauritz Botha to dot down after taking Richard Wigglesworth's long pass five metres out.
Farrell again hooked the attempted extras to leave Ulster just a point adrift 10 minutes into the second period but the home side were dealt yet another substantial blow when Pienaar finally succumbed to the shoulder injury that had threatened to rule him out of the fixture altogether.
Jackson's first kick at goal could and perhaps should have seen Ulster go back in front four minutes later but the Ireland international struck the near post and Saracens remained 10-9 to the good.
Farrell missed his simplest kick from the tee moments later and Ulster's resistance continued as Darren Cave was twice involved in stopping men on the tryline in the same phase of play after Brits had once again done the initial damage.
But the dam eventually looked like it had broken 13 minutes before the end and some 63 minutes after Payne's involvement had finished as Farrell's clever cross kick was picked up over the line by Ashton who claimed his second and Sarries' third try of the match.
Farrell put his past woes behind him to make it a seven-point score and an eight-point ball game as Sarries stretched for home but Ulster refused to read the script and a brace of quick-fire, long-range penalties from Jackson brought them back to within a single strike at goal with seven minutes remaining.
The home side dominated the closing stages as what sounded like the whole of Belfast roared them on but Sarries stood firm and it is they who march on towards what they hope will be a maiden European Cup crown.
Pens: Pienaar 3, Jackson 2
Tries: Ashton 2, Botha
Red card: Jared Payne (Ulster, 4 - foul play, tackling player in the air)
Ulster: 15 Jared Payne, 14 Andrew Trimble, 13 Darren Cave, 12 Luke Marshall, 11 Tommy Bowe, 10 Paddy Jackson, 9 Ruan Pienaar, 8 Nick Williams, 7 Chris Henry, 6 Roger Wilson, 5 Dan Tuohy, 4 Johann Muller (captain), 3 John Afoa, 2 Rory Best, 1 Tom Court.
Replacements: 16 Rob Herring, 17 Andrew Warwick, 18 Ricky Lutton, 19 Iain Henderson, 20 Stephen Ferris, 21 Robbie Diack, 22 Paul Marshall, 23 Craig Gilroy.
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Duncan Taylor, 12 Brad Barritt, 11 David Strettle, 10 Owen Farrell, 9 Richard Wigglesworth, 8 Ernst Joubert, 7 Jacques Burger, 6 Billy Vunipola, 5 Mouritz Botha, 4 Steve Borthwick (captain), 3 James Johnston, 2 Schalk Brits, 1 Mako Vunipola.
Replacements: 16 Jamie George, 17 Richard Barrington, 18 Matt Stevens, 19 Eoin Sheriff, 20 Kelly Brown, 21 Neil de Kock, 22 Charlie Hodgson, 23 Chris Wyles.
Referee: Jérôme Garcès (France)
Assistant referees: Mathieu Raynal (France), Cédric Marchat (France)
TMO: Eric Gauzins (France)