Connacht's hopes of making a push for only the second piece of silverware in their history went up in smoke at Dexcom Stadium when they were blown away by a Racing side who had a man sent off after just 13 minutes and who finished this Challenge Cup quarter-final with just 13 men on the field.
Connacht, who would have had home advantage against Lyon if they advanced to the semi-final, will have huge regrets about letting this opportunity slip from their grasp as they again surrendered a big lead and once more failed to take advantage of having more men on the pitch.
They dominated the opening half but had to be content with a 28-24 lead despite playing with an extra man from the 13th minute after Fijian Wame Naituvi was red carded for a high tackle on Finn Treacy who was about to score in the right corner.
Referee Christophe Ridley also awarded a penalty try which pushed Connacht 21-5 in front, but they were outscored 19-7 from there to the break by a Racing side playing against the breeze.
Connacht laid out their intentions early on, going for the corner with a penalty on the 22 after less than a minute and while that attack was held up illegally, they tapped the next penalty and Finlay Bealham fed Bundee Aki who got through a double tackle to score, with JJ Hanrahan converting for the perfect start.
But Racing hit back after six minutes with Dan Lancaster — with dad Stuart, the former Racing and Leinster coach in the stand — threaded a ball through which Naituvi beat Mack Hansen to for a try.
Hansen and Aki were heavily involved in a fine move which ended with skipper Cian Prendergast scoring his first try and the penalty try and dismissal should have seen Connacht pull away.
But Racing, holding an edge up front, hit back and hooker Diego Escobar scored from a lineout maul down the right at the end of the opening quarter.
Aki knocked on in the tackle a couple of metres short of the line and then Racing struck from deep with Lancaster breaking and his grubber caused mayhem with scrum-half Nolann le Garrec pouncing through three defenders to score a converted try that cut the gap to 21-17.
Connacht responded and were rewarded for targeting the Racing left wing and Prendergast was sent through for his second try which Hanrahan converted from the right for 28-17 after half an hour.
But once again Connacht conceded, again off a lineout maul with centre Josua Tuisova scoring and Lancaster converting to cut the gap to 28-24 at the interval.
Lancaster reduced the margin with a penalty two minutes after the restart but was then short with another effort from 45 metres a couple of minutes later.
Racing then brought in Owen Farrell — dad Andy was in the stand — for Lancaster and with the Racing pack taking control, even scrummaging with just seven men, the French pulled away.
French tighthead Demba Bamba did the hard yards for Le Garrec to get in for his second try which he also converted and then Farrell landed a drop goal off the right post to lead 37-28 after 54 minutes.
Two more penalties from Le Garrec pushed the lead out to 15 points with as many minutes remaining.
Ben Murphy broke to score unconverted try seven minutes from time, while Racing finished the game with 13 men when Farrell was binned for a dangerous clearout on Connacht winger Shane Jennings.
Paul Boyle set Cathal Forde up for a try a minute from the end which Hanrahan converted to reduce the margin to three points, but Connacht were unable to manufacture a match-winner in the final play.
Connacht: Mack Hansen, Shane Jennings, Hugh Gavin, Bundee Aki, Finn Treacy, JJ Hanrahan, Ben Murphy, Denis Buckley, Dave Heffernan, Finlay Bealham, Josh Murphy, Joe Joyce, Cian Prendergast (c), Shamus Hurley-Langton, Sean Jansen. Replacements: Josh Ioane (for Treacy 14), Cathal Forde (for Ioane 15), Peter Dooley (for Buckley 45), Oisin Dowling (for Joyce 45), Dylan Tierney-Martin (for Heffernan 54), Jack Aungier (for Bealham 54), Paul Boyle (for Hurley-Langton 63).
Racing 92: Sam James, Wame Naituvi, Vinaya Habosi, Josua Tuisova, Max Spring (c); Dan Lancaster, Nolann le Garrec; Eddy Ben Arous, Diego Escobar, Demba Bamba; Boris Palu, Will Rowlands; Maxime Baudonne, Junior Kpoku, Jordan Joseph. Replacements: Robin Couly (for Escobar 31-40, 69), Owen Farrell (for Lancaster 47), Henry Chavancy (for Tuisova 51), Lehopoame Leota (for Demba-Bamba 63), Shingi Manyarara (for Rowlands 63), Donovan Taofifenua (for Spring 70).
Referee: Christophe Ridley (England).
