La Rochelle head coach Ronan O’Gara lamented an “unacceptable defeat” after his team fell to a loss that obliterated their hopes of progressing to the Champions Cup knockout stages.
Harlequins defied their awful domestic form to beat the Frenchmen 27-17 at Stade Marcel Deflandre.
England out-half Marcus Smith was sent to the sin bin for a high tackle on Jules Favre in the 56th minute but upon his return, Quins produced the match-winning moment against the 2022 and 2023 champions.
Tom Lawday got the crucial score with eight minutes remaining by storming over with a strong run down the right wing. Man of the match Smith converted the try and added a late penalty to seal it.
Harlequins finished Pool Three…