Saracens' delight at their first league victory on an opponent's ground for nearly a year was tempered by a rib injury suffered by Steve Borthwick. The England captain battled on after receiving lengthy treatment on the hour, refusing to leave the field until the win had been secured. He will know the results of a scan today.

The opening rounds of the Premiership have not been kind to the England team manager, Martin Johnson, and not just because of the general lack of enterprise on display. Injuries are mounting and Quins lost two internationals in the second half of a game that showed how the summer's Bloodgate affair has made them anaemic on the field. The centre Jordan Turner-Hall, a potential replacement for Riki Flutey, suffered a shoulder injury and the wing David Strettle limped off with a foot problem after making one of the few clean breaks of the match.

Borthwick would be a significant loss for Johnson and a cracked rib would leave the lock struggling to make the opening autumn international, at Twickenham against Australia on 7 November. Johnson was derided for keeping faith with Borthwick, not the most demonstrable of leaders, last season, and he was ignored by the Lions, but Borthwick is not afraid to march where others are wary of treading.

Saracens went top of the table with this win, overtaking Wasps, who were playing 24 hours later. They are very much a side in Borthwick's mould – lacking nothing in industry or application, if not easy on the eye. They had been hanging on in their first two matches, but on Saturday they started slowly before throttling their London rivals. Quins have lost two home games this month, without scoring a try. They were beaten only once in the Premiership here last season.

"Steve is a bit of a concern," said Saracens' director of rugby, Brendan Venter. "He showed his courage by staying on the field and he is playing so well for us, a world-class lock. We measure the contributions of our players after games and he came out top after the first two. He is disciplined, honest and hard working and it is very hard for a coach to set a standard and a culture without a captain like Steve."

Sarries closely resemble the Springboks, and not just because they have a number of South Africans in a squad controlled by Venter. Their game plan is simple: they do not play in their own half and they chase kicks strongly, compete on opposition throws and look to isolate opponents at the breakdown. They feed off mistakes and their try here, early in the second half after they had spent most of the opening period on the back foot, followed the Quins full-back, Ugo Monye, dropping a high ball.

Borthwick and the No8, Ernst Joubert, dominated the line-outs; the flanker Andy Saull put Quins under pressure at the breakdown, forcing penalties and turnovers; and Derick Hougaard's boot did the rest.

Venter promised that greater adventure would follow once a club not known for grinding out results week after week have got used to winning. Quins would happily settle for the ugliest of victories. Home advantage was partly negated by a flat atmosphere that was not explained by a stand that is being redeveloped sitting empty. Their head coach, John Kingston, likened the departure of the former director of rugby, Dean Richards, to a bereavement and sensed anxiety among his players. Quins blew three scoring chances.

"You get what you deserve," said Kingston. "We have to take our medicine and move on. We knew Saracens would play in a certain way and kick the ball a lot. We have to look at how much rugby we play, especially the when, where and how."

Harlequins Monye; Strettle (Drauniniu 66), Masson (Clegg 60), Turner-Hall (McMillan 76), Lowe; N Evans, So'oialo (Williams 73); Jones, Botha (Fuga 60), Lambert (Andress 71; Croall 80), Stevenson, J Evans, Robshaw (Guest 67), Skinner (capt), Easter. Pens N Evans 3. Sin-bin J Evans 80.

Saracens Goode; Cato (Haughton 60), Ratuvou, Barritt, Wyles; Hougaard, De Kock (Marshall 76); Gill (Mercey 56), Brits, Nieto (Skuse 69), Borthwick (capt; Ongaro 68), Ryder (Vyvyan 33), Owen (Melck 50), Saull, Joubert.

Try Ratuvou. Con Hougaard. Pens Hougaard 3. Drop-goals Hougaard 2. Sin-bin Wyles 61.

Referee C White (Gloucestershire). Attendance 9,209.