Saracens only victory in their last nine encounters with Gloucester in all competitions was 19-16 at Vicarage Road in the Premiership on 27 September 2009. Gloucester have won on five of their last eight visits to Watford.
Saracens are the form team in Aviva Premiership Rugby with eight successive victories since their 22-28 reversal at Sale on 2 January. This equals Sarries best ever run in the history of the Premiership.
Gloucester host Northampton on Tuesday evening in a rearranged game, but are winless in their last three away matches.
Referee: Dave Pearson (154th Premiership game)
Live on SkySports HD.