Marcelo Bosch's last-gasp penalty gave Saracens the narrowest of victories, 12-11 over Racing-Métro to reach the semi-finals of the Champions Cup.
While the home side played most of the rugby, Saracens showed all their experience, and thanks to Bosch's last-second penalty they crept through as Racing paid the price for their indiscipline.
Maxime Machenaud scored all the points for the home side, with a try and two penalties, but in the end Jonathan Sexton's missed conversion in the first half proved costly.
Much like Leinster had against Bath, Sarries never really threatened to score a try, but thanks to their array of goal-kickers – Charlie Hodgson, twice, and Alex Goode also knocked over three-pointers – they were able to edge ahead when it mattered.
Questions will be asked over the decision to take off Sexton late on, although in truth, the Irishman was a far cry from the man who led Ireland to Six Nations glory.
Saracens were grateful for some desperate defence when under huge pressure, and they will need more of the same if they are to overcome Clermont in Saint-Etienne in a fortnight's time.
Racing had all the possession early on, but it was Sarries who took the lead after an early scrum penalty thanks to a powerful drive from Mako Vunipola.
Still, Racing's ball carriers were making ground, and they should have scored on the quarter-hour when Saracens were powerless to stop a rolling maul, only for Dimitri Szarzewski to knock on over the line.
That followed an earlier dangerous moment when Teddy Thomas found some space out wide, but some cute play by Goode prevented him from chasing his kick through before Racing were over-eager to turn the isolated defender over on the Sarries line.
Saracens came back and had their first real chance with a five-metre scrum after Brice Dulin was forced to touch down in his own in-goal, but Vunipola dropped the scrum after Racing had got the nudge on.
And Racing came straight back, finally getting a reward for the early dominance. After one maul was stopped just short of the line Jim Hamilton cynically prevented it being recycled quickly, and was inevitably sin-binned.
The hosts went straight back to the corner and from their next maul Machenaud peeled away and dived over for the opening try. Sexton couldn't convert in the windy conditions, but Racing led 5-3 after 26 minutes.
Down to 14, Saracens needed to weather the storm, but they did so extremely well, even earning a couple of kickable penalties as Racing's discipline let them down, but twice Hodgson was off-target in the swirling wind.
Racing were almost in again just before Hamilton returned, with Dulin spotting a gap after collecting a high ball and streaked into the Sarries 22. The ball was recycled but Jamie Roberts then tried to crawl for an extra metre and was penalised as a result, allowing Saracens to clear their lines.
While Racing were having the better of the half, their indiscipline was costing them dear, and Hodgson found his range on the stroke of half-time when Camille Gerondeau was called for coming from the side, giving Saracens a 6-5 lead at the break.
In the build-up to that final penalty, Jacques Burger appeared to have thrown a nasty late swinging arm at Machenaud on the ground and he will no doubt be hoping to escape the citing officer's eyes in the same way that it did the officials on the day.
Sarries started the second half as they had finished the first, with Goode slotting a penalty after Racing had gone off their feet at a ruck.
The momentum seemed to be with the visitors, but Racing almost produced a stunning length of the field try to go back in front. Dulin again sparked things, spotting a gap between two forwards to race up to halfway before finding support but the final pass went forward as replacement Alexandre Dumoulin looked to be in the clear.
Racing were coming back into it though, and after Billy Vunipola came in from the side at a maul, Machenaud cut the deficit to a point with 20 minutes remaining.
And when the Saracens scrum buckled with ten minutes to go, Machenaud was on target again, this time from 45 metres out on the right, to give the home side the lead again, 11-9.
Saracens had their chances to come back, most notably when Dulin knocked on a high kick and Maro Itoje got away down the right. He lacked support though and Racing were able to ruck over and win the ball back, before almost coming back with a counter-attack of their own, only for the final pass to drift out of reach of the onrushing Thomas.
Racing got the ball back and just needed to see out the last three minutes, but they tried to pick and go rather than playing for territory, and were made to pay when Nigel Owens spotted them sealing off, handing Bosch the chance to nick it.
It was cruel on Racing, who were much the more enterprising side, but their inexperience showed, with Saracens instead heading to Clermont for a rematch of last year's semi-final.
Pens: Machenaud 2
Pens: Hodgson 2, Goode, Bosch
Yellow Card: Hamilton
Racing-Métro: 15 Brice Dulin. 14 Juan Imhoff, 13 Henry Chavancy, 12 Jamie Roberts, 11 Teddy Thomas, 10 Jonny Sexton, 9 Maxime Machenaud, 8 Antonie Claassen, 7 Camille Gerondeau, 6 Wenceslas Lauret, 5 Francois van der Merwe, 4 Luke Charteris, 3 Luc Ducalcon, 2 Dimitri Szarzewski (c), 1 Eddy Ben Arous.
Replacements: 16 Virgile Lacombe, 17 Julien Brugnaut, 18 Brian Mujati, 19 Fabrice Metz, 20 Thibault Dubarry, 21 Mike Phillips, 22 Johan Goosen, 23 Alexandre Dumoulin.
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Marcelo Bosch, 12 Chris Wyles, 11 David Strettle, 10 Charlie Hodgson, 9 Richard Wigglesworth (c), 8 Billy Vunipola, 7 Jacques Burger, 6 Jackson Wray, 5 Jim Hamilton, 4 George Kruis, 3 Petrus Du Plessis, 2 Jamie George, 1 Mako Vunipola.
Replacements: 16 Schalk Brits, 17 Richard Barrington, 18 James Johnston, 19 Maro Itoje, 20 Kelly Brown, 21 Matt Hankin, 22 Neil De Kock, 23 Nick Tompkins.
Venue: Stade Yves-du-Manoir, Paris
Referee: Nigel Owens (Wales)
Assistant Referees: Ian Davies, Ben Whitehouse (both Wales)
TMO: Derek Bevan (Wales)