Northampton won an intense battle of wills to claim their first Aviva Premiership title in dramatic late fashion and leave Saracens crestfallen at Twickenham.
For the first time in Premiership history the final went to extra-time, but it was Saints who prevailed 24-20 with an Alex Waller try that required intensive television match official adjudication in the game's final play.
The defeat was another shattering experience for Saracens just seven days after they suffered Heineken Cup final heartache against Toulon.
Charlie Hodgson's two penalties after it finished 14-14 following 80 minutes of fierce combat looked to have seen Saracens home, but Saints had one more attack left in them and replacement forward Waller pounced for a score that Stephen Myler converted.
Owen Farrell earlier kicked three penalties and centre Marcelo Bosch scored a try for Saracens, while Northampton claimed touchdowns through full-back Ben Foden and centre George Pisi, with Myler booting both conversions and landing an extra-time penalty.
A cramped-up Farrell went off in the second half, just 48 hours before he flies to New Zealand and joins England's tour squad.
And he was also at the centre of the game's most controversial moment after he claimed a seemingly-good try that referee J P Doyle concurred with, before Doyle belatedly required a TMO verdict and the try was ruled out for a forward pass in the build-up.
It was a cruel blow for Saracens and led to them ending a season that promised so much without a trophy as former England forwards Steve Borthwick and Matt Stevens made their farewell appearances.
They kept their nerve during most of a frenzied finale, but they ultimately ran out of time.
The opening flurries were tense and riddled with mistakes and, although Northampton dominated in terms of territory, it was Saracens who went ahead when Farrell landed a 35-metre penalty after 11 minutes.
Saracens had been content to absorb Saints' pressure amid the initial sparring and they doubled their lead when Farrell slotted a second penalty six minutes later.
Northampton needed to shake off Saracens' suffocating approach and it arrived 10 minutes before the break when wing Ken Pisi broke free from deep inside his own half.
Saracens had sufficient defensive numbers to thwart the danger, but it proved only a temporary reprieve as Saints capitalised in devastating fashion.
Myler sparked an attack 10 metres out and the finish was clinical as Luther Burrell and Pisi combined to send Foden over, with Myler's conversion putting Northampton 7-6 ahead.
There was little to enthuse a packed house, though, with neither side able to produce any sustained passages of attacking play, but Northampton marginally deserved their lead following Pisi's welcome outbreak of imagination.
Farrell put Saracens back in front through a 45th-minute penalty, but back came Northampton as they exerted another spell of sustained pressure that stretched their opponents on both flanks.
Northampton eagerly looked to release their Wales and British and Irish Lions wing George North at any opportunity, yet Saracens' well-organised defence ensured there were sufficient numbers to halt his juggernaut threat.
Saints skipper Dylan Hartley appeared off the bench after 55 minutes for his first outing since suffering a shoulder injury two months ago, suggesting he will be ready to join England's tour party in New Zealand early next week.
Hartley, who was sent off in last season's Premiership final and received an 11-week ban that meant he missed the British and Irish Lions tour of Australia, had unfinished business at Twickenham.
And his arrival coincided with Northampton looking to increase the tempo as a tight, tense final approached its final quarter.
Saints possess a prolific force in North and it was his power and destructive capability that smashed Saracens' defence out wide and set up a chance for the midlanders to pounce.
And Myler did not require a second invitation, as his superbly-placed kick was gathered by Pisi for Northampton's second try that Myler again converted.
Saracens looked to have drawn level with 18 minutes remaining when Farrell finished off a move sparked by Goode and Chris Wyles, but referee Doyle disallowed the try after initially appearing to award it as he belatedly referred matters to television match official Graham Hughes.
It was a defining moment, but one that went in Saints' favour as they closed in on a second piece of silverware in eight days.
But Saracens were not finished and they drew level seven minutes from time after brilliant approach work by hooker Schalk Brits led to a try for Bosch before Hodgson's conversion attempt hit a post.
And it meant the final going to an added 20 minutes for the first time in the event's 12-year existence, with Hodgson's penalty double edging Saracens ahead before Waller provided stunning late drama.