A penalty try completed Quins’ remarkable turnaround with five minutes to go, with prior scores Cadan Murley (2) and Danny Care helping them on their way.

But Racing, who crossed through Gael Fickou, Kitione Kamikamica and Francis Saili, hit back seconds later through Le Garric’s effort despite having 12 men on the pitch amid three late yellow cards, one of which went to fly-half Finn Russell after he had tallied 12 points from the tee.

Racing struck first after a series of offloads eventually released full-back Warrick Gelant on the right, who unselfishly laid the ball back inside for centre Fickou to finish.

In contrasting conditions to their Round 2 encounter at a sodden Twickenham Stoop, both sides were looking for the offload on the dry, artificial turf at Paris La Defense Arena, though try-line action was at premium over the 20 minutes following Racing’s score.

Fly-half Marcus Smith put Quins on the board with a penalty on 24 minutes, but he couldn’t repeat the feat from halfway moments later after the Racing front row was dismantled in a scrum.

The athleticism from @wacker96 🙌
The composure from @cadan_murley 👏#HeinekenChampionsCup | @Harlequins pic.twitter.com/k8Sslh5Yu1

— Heineken Champions Cup (@ChampionsCup) January 15, 2023

Quins then looked to have notched their first try of the game on half an hour as wing Aaron Morris bundled over out wide, but a late TMO intervention chalked the score off amid no clear grounding.

In a cruel blow for the visitors, Racing then marched down the other end to cross for a second time, replacement back-row forward Kamikamica hitting a brilliant line to dive over unchallenged.

The hosts took a 14-3 lead into the second half, and that was increased 20 seconds after the restart as they exploited a dog leg in the Quins defence with some fast hands and put centre Saili over.

Moments after the TMO ruled out another score, Quins finally dotted down for the first time on 45 minutes, scrum-half Care darting round the corner after a maul was halted just short.

The breathless start to the second half continued as Racing almost found an instant response through Juan Imhoff, but the wing grounded just beyond the Quins dead-ball line as he raced onto a kick in behind.

Quins then cut the gap to four points as Smith threw a brilliant dummy and scythed through the Racing defence before teeing up wing Murley, who finished clinically.

There was a setback moments later, though, as Morris was sin-binned for taking Racing counterpart Donovan Taofifenua out in the air, with a Russell penalty then extending the home team’s lead on 55 minutes.

5️⃣ teams qualified from Pool A this weekend!

Congratulations to @leinsterrugby, @SharksRugby, @Saracens, @ExeterChiefs and @EdinburghRugby who have reached the #HeinekenChampionsCup Round of 16 👏

Where are your team in the standings? pic.twitter.com/bDQ5KD8GbQ

— Heineken Champions Cup (@ChampionsCup) January 15, 2023

Quins were down to 13 men on 58 minutes as a breathless passage of play ended with No.8 Alex Dombrandt infringing metres from his own line, but they defended heroically to keep Racing out during their two-man disadvantage.

With 14 men on the pitch, Quins then produced some scintillating running rugby to release Murley for his second of the afternoon, but Smith couldn’t convert to leave his side trailing 24-22.

Another Russell penalty increased Racing’s lead to five points, but after Dombrandt returned, Quins piled on the pressure.

Taofifenua and replacement prop Eddy Ben Arous were both sin-binned for Racing, with Russell then also seeing yellow as his deliberate knock-on handed Quins a penalty try.

With three minutes to play against 12 men, Quins led 29-27, but an infringement seconds after the restart handed Le Garrec the chance to put Racing back in front, which he duly took before his side held on for a dramatic win.

Both teams’ knockout stage hopes go down to the final round of pool stage games next weekend as Racing visit Leinster Rugby and Harlequins host Cell C Sharks, both on Saturday.