Six second-half points from the boot of full-back Alex Goode stunned Leicester as Saracens recorded a 15-14 victory at Welford Road on Saturday.
Goode kicked five penalties as Sarries ended Tigers' nine-match Aviva Premiership winning streak.
The Tigers, who edged out Sarries in last season's memorable play-off final at Twickenham, could have snatched victory but rookie centre Billy Twelvetrees missed a late penalty.
The visitors led when Goode kicked a penalty after just minutes, yet the Tigers steadied themselves and gradually moved through the gears.
A penalty from Staunton got them off the mark and although another three-pointer from Goode restored Saracens' lead, Staunton booted Leicester level with his second penalty.
Leicester produced a fine try in the 29th minute when England Saxons youngster Tuilagi evaded David Strettle and Owen Farrell to go over. Staunton converted another penalty but Goode quickly cancelled that effort out with a third penalty of his own.
Sarries sought a response as they hammered away in the Tigers 22, they battered away through countless phases but the Tigers held firm.
A powerful Sarries scrum then saw the Leicester front row concede a penalty which Goode slotted with 15 minutes to play to close the gap to just two points.
Staunton missed a penalty after Adam Powell was adjudged to have held Alesana Tuilagi back.
And the miss proved costly as Goode slotted the winning kick with five minutes remaining as Leicester flopped off their feet at a ruck. There was one last chance for Leicester, but Twelvetrees was off target with the boot.
Try: M Tuilagi
Pen: Staunton 3
Pen: Goode 5
Leicester: 15 Scott Hamilton, 14 Horacio Agulla, 13 Manu Tuilagi, 12 Anthony Allen, 11 Alesana Tuilagi, 10 Jeremy Staunton, 9 James Grindal, 8 Thomas Waldrom, 7 Craig Newby (c), 6 Tom Croft, 5 George Skivington, 4 Steve Mafi, 3 Julian White, 2 George Chuter, 1 Marcos Ayerza.
Replacements: 16 Rob Hawkins, 17 Boris Stankovich, 18 Martin Castrogiovanni, 19 Calum Green, 20 Ben Woods, 21 Sam Harrison, 22 Dan Hipkiss, 23 Billy Twelvetrees.
Saracens: 15 Alex Goode, 14 David Strettle, 13 Rodd Penney, 12 Brad Barritt, 11 Chris Wyles, 10 Owen Farrell, 9 Richard Wigglesworth, 8 Ernst Joubert, 7 Andy Saull, 6 Justin Melck, 5 Mouritz Botha, 4 Steve Borthwick (c), 3 Carlos Nieto, 2 Schalk Brits, 1 Rhys Gill.
Replacements: 16 Jamie George, 17 Jared Saunders, 18 Matt Stevens, 19 Hugh Vyvyan, 20 Kelly Brown, 21 Neil de Kock, 22 Adam Powell, 23 James Short.
Referee: Sean Davey
Assistant referees: Paul Dix, Kevin Stewart