It began with two England front-­rowers clashing in the tunnel, endured a shocking injury that left both sides visibly shaken and there were times the home faithful turned on one of their former players – this was a feisty London derby that went the way of Harlequins, who basked in the glory of finally beating Saracens at the ninth time of trying.

Admittedly, the “clash” between Joe Marler and Jamie George was entirely in jest and you would have to go some to find a more polite chorus of boos than that from the Harlequins supporters but this was a keenly fought derby that had the ultras of suburbia off their feet and roaring with delight at the final whistle.

For there is no little animosity between these sides and a first win for Harlequins over Saracens since ­January 2020 felt long overdue for the home crowd. That it was thoroughly deserved, on the back of tries from Fin Baxter and ­Lennox Anyanwu and owing every­thing to their defensive defiance, will make it all the more sweet. It was a feather in the cap for Harlequins’ defence coach, Jason Gilmore, with Jack Kenningham and Dino Lamb excelling and some way to round off the Premiership’s derby weekend.

The significant sour note was the awful ankle injury sustained by Saracens’ Andy Onyeama-Christie, who was taken to hospital with a suspected fracture and dislocation. He has fought his way back from two broken arms in the past few years and had started the season in fine fettle, making his injury all the more dispiriting. It capped a miserable afternoon for Saracens, who arrived as the only side with a 100% record but went home with just a ­losing bonus point. “[We’re] so gutted. He’s been playing brilliantly for us so for that to happen is horrendous,” said the Saracens director of rugby, Mark McCall. “But we’ll look after him and we’ll get him back.”

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A scoreless opening quarter was notable only for Onyeama-Christie’s injury. He carried hard close to the Harlequins line but went down in a heap after he was tackled. The ­reactions of teammate Marco ­Riccioni and opponent Stephan ­Lewies said everything about the severity of the injury.

Harlequins lost James Chisholm to the sin-bin soon after when he cynically played the ball on the floor as Saracens threatened but the hosts held firm while down to 14 in a ­demonstration of their defensive prowess. Their inside-centre, Anyanwu, caught the eye in that respect, with the ball in hand too, ­carrying hard and determined to make himself a mainstay of the team now that André Esterhuizen has left.

With 25 minutes on the clock ­Marcus Smith kicked a penalty to the corner. The maul did not get very far but after a number of ­forwards bashed away at the Saracens line, Baxter was over for the opening score. ­Compounding matters for Saracens they lost another back-rower, Juan Martín González, to an arm injury before the half was up. That meant the introduction of the bench of Hugh Tizard, a former Harlequins second-row and academy graduate. There was not much sign of an “away end” forming at the Stoop but, in a nod to the bad blood that does exist between these two sides, there was a smattering of booing from some Harlequins supporters.

They had their say, too, when ­Tizard reached out and forced the ball on to the line for Saracens’ first points of the match, nearly 10 minutes into the second half before Alex Lozowski’s conversion levelled the scores at 7-7. A moment of magic from Smith put Harlequins back in the ascendancy, however. He jinked his way through the Saracens defence near halfway and if he could not quite wriggle free he had the wherewithal to find Will Porter, who fizzed a pass wide for Anyanwu to score on the right.

A missed Lozowski penalty with 15 minutes to go suggested Saracens were both running out of ideas – “a big moment” said the Harlequins head coach, Danny Wilson – and still unable to find their usual accuracy and with nine minutes to go, Smith made no mistake from the tee. A more straightforward effort for Lozowski brought a draw into the equation but Saracens never really looked like securing it.