Fly-half Charlie Hodgson kicked 23 points as Saracens moved back into second place in the Aviva Premiership table with a 28-23 victory over Gloucester at Vicarage Road.
Hodgson, returning to the side after four weeks out with a fractured cheekbone, landed seven penalties and a conversion but they were pushed all the way by Gloucester who competed superbly but were ultimately sunk by replacement Richard Wigglesworth's crucial second-half try for Sarries.
Gloucester, who had two players sin-binned, replied with tries from prop Dan Murphy and flanker Akapusi Qera, with Billy Twelvetrees kicking their other 13 points.
Twelvetrees, switched from centre to fly-half with Freddie Burns on England duty as a replacement in the Twickenham triumph over New Zealand, kicked Gloucester into an early 6-0 lead with penalties in the second and seventh minutes.
Hodgson's second penalty levelled the scores at 6-6 in the 27th minute but, two minutes later, Gloucester scored the first try of the match after the former England fly-half's clearance kick was charged down.
Prop Murphy, who blocked the kick, produced a neat one-touch to control the ball with his boot and a clean pair of hands to collect it and drive over the line, with Twelvetrees converting. Hodgson booted a penalty as Murphy was sin-binned and added another to reduce the deficit to a single point four minutes before the interval.
Hodgson struck again to kick Saracens ahead three minutes into the second half but the Cherry and Whites responded with number eight Sione Kalamafoni making a surging run through the middle from the halfway line before their pack mounted a concerted series of forward drives.
They moved the ball wide before Qera crashed over in the left corner, with Twelvetrees adding the conversion from the touchline.
Kalamafoni blatantly killed the ball at a ruck and was yellow-carded. Hodgson landed his sixth penalty in the 54th minute and Saracens took the lead when full-back Chris Wyles split the Gloucester defence before releasing Wigglesworth who crossed in the corner for a real winger's try, converted by Hodgson.
Twelvetrees cut the gap to two points with his third penalty before Hodgson responded with his seventh and Gloucester mounted a desperate late assault which saw Wigglesworth sin-binned but Saracens managed to soak up the pressure.