Saracens ground out an unconvincing 16-10 victory over newly-promoted Worcester at Vicarage Road on Sunday.

Worcester fully deserved their first Zurich Premiership bonus point as they battled on bravely despite Saracens, off-colour after their opening week victory, boasting a powerful front row which was dominant in the scrum.

Cobus Visagie, the South African tight-head, caused the Warriors' front row all sorts of problems but Worcester were effective in the loose and moved into a 7-3 lead with a well-worked try from hooker Steven Sparks.

Saracens hit back through winger Paul Bailey and although Worcester held a 10-8 advantage at half-time they lacked the cutting edge of an experienced top-flight side and could not improve their lot after the interval.

Dan Scarbrough scored his first try for Saracens and two penalties from Thomas Castaignede proved the difference as the Men in Black secured their second narrow win of the season.

Rod Kafer's side opened the campaign with a surprise victory over champions Wasps at Twickenham last weekend and captain Hugh Vyvyan had cautioned his players against making any assumptions against the newly-promoted Worcester.

And any complacency would have been shot out of them as early as the fifth minute, when Saracens were stung immediately after Castaignede has opened the scoring with a penalty.

Simon Raiwalui failed to gather the ball cleanly and the powerful centre Tommy Hayes charged forward, deep into Saracens territory to give Worcester's attack unstoppable momentum.

For phase after phase Worcester's forwards, presenting quick ball, picked and drove to within a metre of the line from where Sparks burrowed over for the Warriors' first Premiership try.

Worcester had played with spirit last week against Newcastle but were outclassed by a Falcons side somewhat below their best.

Although conceding five penalties at the scrum in the first half, the Worcester pack was superior at the breakdown and heaped pressure on Saracens in the loose and the hosts took until the 22nd minute to forge their first opening.

Castaignede launched a long cross-field pass that former All Black Taine Randell scooped up off the ground before shifting it outside to Bailey.

The winger, awarded a new contract with Saracens at the end of his first full season last year, cut inside and slipped around three covering Worcester defenders to regain Saracens the lead.

Worcester's early bravado had been laudable but the penalties at the scrum were proving costly and coach Andy Keast replaced the struggling Sparks with Tony Windo.

Worcester soon had Saracens reeling on their own scrum and Hayes converted the subsequent penalty with a monster effort from inside his own half to earn the half-time advantage.

Saracens regrouped at half-time and showed more invention through Castaignede and Mark Bartholomeusz with Richard Haughton, a replacement for Bailey at the end of the first half, a potent attacking threat out wide.

The England Sevens star thought he had touched down in the right corner only for referee Chris White to award Saracens a contentions five-metre scrum.

Again they were driven off the ball but Worcester could not clear it, some quick-witted sniping from Richard Hill won Saracen back the ball and the ball was fed wide to Scarbrough for first try since moving to Vicarage Road from Leeds.

Castaignede extended that lead to 16-10 with a second penalty and while Worcester had lost their momentum from the first half, they were not content with just a first Premiership point but continued to push for victory.

But they could find no chink in the Saracens armour and eventually were thankful for Nicky Little's scuffed penalty from in front of the post for preserving their bonus point.