Borthwick refused to be substituted until Saracens had secured a third straight victory that tonight leaves them top of the Guinness Premiership table.

England will also have major concerns over Jordan Turner-Hall, who was tonight undergoing an x-ray on a shoulder injury, and his Quins team-mate David Strettle, who has another potential foot problem.

Saracens director of rugby Brendan Venter admitted the loss of Borthwick would be a major blow for both club and country given the way he has started the season.

England’s first Test is against Australia on November 7.

Venter said: “Steve is a little bit of a worry for us. He will have a scan tomorrow and we will see how his rib is. He is just so courageous. He hurt his rib but he stayed on the field for which I am massively thankful.

“He is playing really well, which is fantastic for England. He is a serious world-class international lock.

“It would be a blow (if it turns out to be a broken rib) but we will deal with that if it comes.

“It is very hard for a coach to set a standard and a culture if you don’t have a captain like that.

“If you talk about a disciplined, honest, hard-working individual then Steve Borthwick fits that bill 100%. I have been very blessed to have a captain like that.

“In our first two games this season Steve had the most contributions and the second most contributions. We measure everything - tackles, ball carries, his rucking, his defensive play - and he is right at the top of our team.”

Harlequins were tonight assessing the state of Turner-Hall, who is a live contender to replace the injured Riki Flutey as England’s inside centre for the autumn.

Turner-Hall’s anticipated showdown with Saracens’ own contender Brad Barritt never sparked into life as the Men in Black persisted with their a game-plan dominated by the boot.

Derick Hougaard kicked 17 points, including two drop goals, and Harlequins knew they had a mountain to climb when Kameli Ratuvou scored Saracens’ try early in the second half.

The scores had been 6-6 at the interval but Saracens had spent the majority of the half just soaking up pressure and kicking the ball.