Harlequins thrashed Saracens in their London rivals' first Premiership match since their automatic relegation for salary cap breaches was confirmed.

Danny Care's early score and two Cadan Murley tries, before Sarries' Alex Lozowski crossed, put Quins in command.

Gabriel Ibitoye and Paul Lasike then touched down shortly after the break.

Dom Morris' try cut the arrears but Martin Landajo sealed an emphatic win against a team essentially playing the first of 14 meaningless games.

Care's try, which came after just 78 seconds, was evidence of the hosts' intensity, something lacking from a Sarries team with nothing to play for in the league.

Mark McCall's side battled gamely, but rarely made the match a contest against a Harlequins team set on deepening their rivals' misery.

Following what the Saracens director of rugby had described as their "most difficult week of the season" in the build-up, he was dealt a further blow by the late withdrawal through injury of experienced captain Brad Barritt.

And, without a large contingent of players away on Six Nations duty, Sarries could not produce the same against-the-odds performance that secured a place in the knockout stage of the Champions Cup just 24 hours after their relegation had been confirmed.

Harlequins, who themselves suffered a late injury withdrawal, that of Ross Chisholm, which took their number of absentees to 19, seemed keen to make the most of the Premiership and European champions' turmoil by starting the match at a frightening pace.

Care crossed with the game's first attack after a superb break from halfway and one-two with number eight Alex Dombrandt who, along with fly-half Marcus Smith, was outstanding throughout.

Another early try followed when Dombrandt's turnover launched a counter-attack and sent Murley over in the corner.

The wing would soon cross again thanks to brilliant creativity from Smith, whose dummy left the Sarries defence totally flat-footed.

Lozowski went under the posts to make the first half appear closer than it was, as wet, muddy conditions took hold at The Stoop, but Ibitoye and Lasike touched down shortly after the break to put the result beyond doubt and secure a bonus point.

Sarries continued to fight hard, and were rewarded with Morris' try, but just as they appeared to be finishing on some sort of positive, an error in defence gave Landajo the easiest of scores to cap a superb afternoon for Quins and a miserable week for Saracens.

Harlequins head of rugby Paul Gustard told BBC Radio London:

"To score 40 points is always the sign of a good performance I think, but it was the execution that we had overall - aggression in our defence, dominance in our set-piece and the ambition that we played with in our attack.

"The weather wasn't the greatest but I think we showed that if you have the courage to play and you get momentum, then you can hurt teams and we've got players who can do that.

"I think we really respected the badge today."

Saracens director of rugby Mark McCall told BBC Radio London:

"There's obviously been a lot going on over the last 12 weeks, but last week in particular felt extremely difficult.

"It was the reality that we are going to be relegated and the players having concerns about what that means for them.

"It was a really difficult week with a lot of emotions. There were a lot of conflicting emotions, individually and collectively and I think you probably saw that on the field today."

Harlequins: Morris; Murley, Penny, Lasike, Ibitoye; Smith, Care; Garcia Botta, Elia, Collier, Lewies, Symons, J Chisholm, Robshaw (capt), Dombrandt.

Replacements: Musk, Auterac, Kerrod, Cavubati, Kunatani, Landajo, Herron, Goneva.

Saracens: Gallagher; Lewington, Lozowski, Morris, Segun; Manu Vunipola, Wigglesworth (co-capt); Barrington, Singleton, Koch, Hunter-Hill, Kpoku, Isiekwe, Clark, Wray (co-capt).

Replacements: Woolstencroft, Lamositele ,Ibuanokpe, Christie, Reffell, Spencer, Watson, Obatoyinbo.

Referee: Luke Pearce (RFU).