|Racing Metro (5) 11|
|Try: Machenaud Pens: Machenaud 2|
|Saracens (6) 12|
|Pens: Hodgson 2, Goode, Bosch|
Marcelo Bosch's last-gasp penalty sent Saracens into the European Champions Cup semi-finals in dramatic style.
The centre drilled a long-range effort through the posts to sink Racing Metro with the last kick of the match.
Saracens led 6-5 at the break, two Charlie Hodgson penalties bookending a Maxime Machenaud try.
Alex Goode landed a third Saracens kick before Machenaud looked to have won it with two of his own, but Racing killed the ball and Bosch their hopes.
Saracens will play another French side, Clermont Auvergne, in the last four in Saint Etienne on 18 April, while two-time defending champions Toulon will meet Leinster the following day in the other semi.
The hosts had looked poised to reach a maiden semi-final in top-level European competition after Machenaud stroked over his two penalties, but they were responsible for their own downfall as they attempted to run down the clock on their own 10-metre line in the closing moments.
|European Champions Cup semi-final line-up|
|Clermont Auvergne v Saracens (Saturday 18 April, 1515 BST)|
|Toulon v Leinster (Sunday 19 April, 1515 BST)|
Referee Nigel Owens hawkishly watched a series of one-out runners trundle into contact to set up a ruck, and when a Racing support player went off his feet, he did not hesitate to penalise the Paris side.
With first-choice kicker Hodgson having suffered a blow to the leg and Goode lacking the range, 31-year-old Argentina centre Bosch stepped up and belted the ball between the posts to bring about wild celebrations from last year's beaten finalists.
Hodgson had put Saracens in front with an early penalty before Racing - who should have scored when they dropped the ball over the line from a driving maul - took the lead as Machenaud went over for what proved to be the game's only try.
Hodgson, who had already missed two penalties, restored Sarries' advantage just before half-time and Goode edged them further ahead, but Racing then took control of the match.
Two Machenaud penalties appeared to have secured the Parisians a narrow win, but as they attempted to seal victory they sealed off the ball at a ruck, leaving Bosch to send Sarries into the semi-finals.
Saracens match winner Marcelo Bosch:
"With kicks like this you're either the hero of the day or the bad guy, so I'm happy that it went my way. I just stayed relaxed and fortunately it went through the posts.
"Sometimes they ask me if I'm keen to take the long-range kicks and because of the wind it was not a good distance for the other kickers. I said 'why not? I can take it' and the rest is history."
Saracens boss Mark McCall:
"We weren't great in the first half even though we had a very strong wind behind us. But that's where it turned around and I'd say our second half performance was as courageous, brave and hard working as I've seen.
"We went hunting and kept knocking them down and scrapped for absolutely everything."
Racing Metro 92: Dulin; Imhoff, Chavancy, Roberts, Thomas; Sexton, Machenaud; Ben Arous, Szarzewski, Ducalcon, Charteris, Van Der Merwe, Lauret, Gerondeau, Claassen.
Replacements: Goosen for Imhoff (57), Dumoulin for Roberts (51), Phillips for Sexton (76), Brugnaut for Ben Arous (52), Lacombe for Szarzewski (52), Mujati for Ducalcon (52), Metz for Van Der Merwe (76), Dubarry for Gerondeau (56).
Saracens: Goode; Ashton, Bosch, Wyles, Strettle; Hodgson, Wigglesworth; M Vunipola, George, Du Plessis, Kruis, J Hamilton, Wray, Burger, B Vunipola.
Replacements: De Kock for Wigglesworth (65), Brits for George (54), Johnston for Du Plessis (52), Itoje for J Hamilton (57), Brown for Wray (52), Gill for B Vunipola (54).
Not Used: Hankin, Tompkins.
Sin Bin: J Hamilton (27).
Ref: Nigel Owens (Wales).