A last-minute penalty from Sam Vesty helped Leicester Tigers to a 16-13 win at Saracens on Sunday, making the Tigers the first team to qualify for the Guinness Premiership semi-finals.
Scott Hamilton touched down in the first half, Sam Vesty added a penalty and Ayoola Erinle went over in the second for the visitors before Jackson levelled matters with a penalty.
The hosts' fly-half hit the post with a late penalty before Vesty - with one success out of his previous four attempts - slotted the match-winning penalty with the last kick of the game.
Leicester remain top of the standings, while Wasps' bonus-point win at Bristol hampers Saracens' play-off hopes.
It was the end of an era for the Men in Black.
Toulon-bound Kris Chesney was making his last home appearance for Saracens - his 338th in all - while Andy Farrell and Cobus Visagie both stepped off the bench for their final bow at Vicarage Road.
Farrell will be part of the so-called South Africanisation at Saracens next season as skills coach under incoming director of rugby Brendan Venter, a former Springbok.
Saracens chief executive Ed Griffiths has vehemently denied the club will be overhauled, insisting it will remain "emphatically English".
It was a cosmopolitan Italy-England-Argentina connection which brought Saracens' first score.
Fabio Ongaro's long throw overshot the lineout where Hugh Vyvyan swept up and, with the handling of a basketball player, eluded Vesty and deftly popped the ball to Lionelli to score unopposed under the posts. Jackson popped over the conversion.
The Tigers soon replied after 10 phases and 27 pairs of hands when wing Hamilton evaded Vyvyan's grasp around the fringes to score wide on the right.
Vesty pulled the conversion wide and Jackson then missed a straight-forward penalty attempt at the other end before slotting an even easier effort from inside the visitors' 22.
An indiscretion at a ruck offered Vesty three points which he gratefully accepted to cut the interval deficit to two.
Tigers fly-half Vesty missed a close-range penalty before the visitors took the lead for the first time after two bursts through the middle.
Replacement scrum-half Ben Youngs scythed through a gap at a ruck on halfway and two phases later England centre Dan Hipkiss was stopped five metres short after an incisive break.
Leicester regrouped and spread the ball wide where centre Erinle touched down. Vesty's kicking woes continued as he missed the conversion.
Tom Croft, who is expected to be named among the British and Irish Lions touring party for South Africa on Tuesday, had few opportunities to impress from the second row.
The England flanker burst down the left wing but ran out of support before Saracens' lead was restored.
Jackson drilled over a penalty following an offside in the middle of the field before Chesney trudged off the Vicarage Road surface for the final time.
Jackson hit the upright with a late penalty attempt before Saracens were ruled to have strayed at a ruck and Vesty slotted the ball through the posts from 30 metres.
Pens: Jackson 2
Tries: Hamilton, Erinle
Pens: Vesty 2
Saracens: 15 Alex Goode, 14 Chris Wyles, 13 Francisco Leonelli, 12 Brad Barritt, 11 Rodd Penney, 10 Glen Jackson (capt), 9 Neil de Kock, 8 Justin Melck, 7 David Seymour, 6 Chris Jack, 5 Kris Chesney, 4 Hugh Vyvyan, 3 Tom Mercey, 2 Fabio Ongaro, 1 Matias Aguero.
Replacements: 16 Matt Cairns, 17 Cobus Visagie, 18 Tom Ryder, 19 Don Barrell, 20 Justin Marshall, 21 Andy Farrell, 22 Noah Cato.
Leicester: 15 Geordan Murphy (captain), 14 Scott Hamilton, 13 Ayoola Erinle, 12 Dan Hipkiss, 11 Johne Murphy, 10 Sam Vesty, 9 Julien Dupuy, 8 Jordan Crane, 7 Ben Woods, 6 Craig Newby, 5 Ben Kay, 4 Tom Croft, 3 Martin Castrogiovanni, 2 George Chuter, 1 Marcos Ayerza.
Replacements: 16 Benjamin Kayser, 17 Dan Cole, 18 Dan Hemingway, 19 Ben Pienaar, 20 Harry Ellis, 21 Seru Rabeni, 22 Tom Varndell.
Referee: David Rose
Touch judges: Andy Watson, Ken Stewart
Assessor: Steve Lander
Television match official: John Burtenshaw