Late rally not enough
A fast start and a gutsy finish ensured Northampton Saints upset table toppers Saracens 27-13 in their play-off clash and secured a spot in the Premiership Grand Final for the first time in their history.
Five times Saints have lost at the semifinal stage and few gave them much of a hope of making it sixth time lucky against a Sarries side that were unbeaten at their new home of Allianz Park.
But tries from Brian Mujati and Jamie Elliott deservedly put the visitors in front before the half-hour mark and they held off a late rally from Saracens to set up a final against local rivals Leicester Tigers.
Duncan Taylor's second half try and the boot of Owen Farrell threatened a fight back but in truth Northampton, who scored a third try through replacement GJ van Velze, more than deserved their famous victory.
They came roaring out of the blocks, making a mockery of the fact that they have not won away at their London rivals in nine years, and should have hit the front inside two minutes.
But after a huge tackle from Soane Tonga'uiha had upended Schalk Brits and a penalty had been won at the subsequent breakdown Stephen Myler's scuffed his effort badly and it fell short.
Saints were clearly up for the battle though and after some fantastic offloading involving almost every player in their side winger Ken Pisi found space deep inside the Sarries' 22 and although the move broke down referee JP Doyle was playing advantage and Myler had a second chance to open the scoring but yet again he was off target.
For all their early territorial dominance that meant Northampton had nothing to show for it and Saracens gradually established a foothold in the match, although the early loss of Charlie Hodgson to injury did not help their cause.
But there was no doubt that the Northampton pack was shading the opening exchanges however and their calling card this season, the driving maul, brought them the first try of the afternoon and put them deservedly in front.
The pack rumbled up towards the line down the right and Mujati, in his final season for the club, burrowed his way over leaving the TMO to award the try, Myler adding the extras from the touchline for 7-0.
Only moments later and Saints were in dreamland, Tonga'uiha securing quick turnover ball and releasing scrum-half Lee Dickson and when the ball was fed left it was the in-form Elliott who sped away to the corner, Myler again on target with the conversion for 14-0.
Sarries were rattled and when Farrell took Myler out with a late hit the Saints No.10 picked himself up to fire home the penalty and a 17-0 lead at the half hour mark.
Mark McCall's side now badly needed a response and something to take into the half-time break but a horrific first period was summed up when Farrell dragged a simple penalty wide of the uprights.
A sustained period of Saracens pressure was inevitably going to arrive after the break and when Strettle broke through down the right it looked like their first try had arrived.
But James Wilson had other ideas and his last-ditch tackle held up the former Harlequins flyer and when full-back Ben Foden arrived on the scene there was enough muscle there to prevent Strettle grounding the ball.
Saracens still had the put-in at a five metre scrum but Mujati and Tonga'uiha turned the screw and won a penalty for Saints to finally clear their lines for the first time in the second half.
It took until the 50th minute for Saracens to finally get on the board, Farrell splitting the uprights with a penalty from near halfway to reduce their arrears to 17-3.
Five minutes later and Farrell was at it again, slotting another penalty after Christian Day was caught on the wrong side of a driving maul in front of his own posts.
But Saints refused to retreat into their shell and after a series of pick and drives took them into the 22 they had their third try on the hour mark, Dickson alert to release GJ van Velze down the short side and the replacement slid over almost unopposed.
Myler's conversion made it 24-6 and Saints seemed home and dry but Elliott's sin-binning for taking out Farrell in the air breathed new life into Sarries.
First it was Hodgson's replacement Taylor who snuck over on the left wing and when Farrell added the conversion it was only 24-13 and Saracens had 15 minutes to save their season.
Saints looked out on their feet as the game opened up with both sides guilty of wasting possession but it remained Sarries in the ascendancy as the game entered the last ten minutes.
But a key steal by Samu Manoa at a lineout on Saints' own try line relieved some pressure and when replacement Tom May won a penalty Myler was on hand to effectively seal the victory from the kicking tee.
Saracens refused to give in during the game's closing stages but they had no answer for Northampton's fantastic physicality that carried them to Twickenham.
Pens: Farrell 2
For Northampton Saints:
Tries: Mujati, Elliott, Van Velze
Cons: Myler 3
Pens: Myler 2
Yellow card: Jamie Elliott (Northampton Saints, 60)
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Joel Tomkins, 12 Owen Farrell, 11 David Strettle, 10 Charlie Hodgson, 9 Neil de Kock, 8 Jackson Wray, 7 Will Fraser, 6 Kelly Brown, 5 Alistair Hargreaves, 4 Steve Borthwick (captain), 3 Matt Stevens, 2 Schalk Brits, 1 Mako Vunipola.
Replacements: 16 John Smit, 17 Rhys Gill, 18 Carlos Nieto, 19 Mouritz Botha, 20 George Kruis, 21 Richard Wigglesworth, 22 Duncan Taylor, 23 Chris Wyles.
Northampton: 15 Ben Foden, 14 Ken Pisi, 13 James Wilson, 12 Luther Burrell, 11 Jamie Elliott, 10 Stephen Myler, 9 Lee Dickson, 8 Samu Manoa, 7 Tom Wood, 6 Calum Clark, 5 Christian Day, 4 Courtney Lawes, 3 Brian Mujati, 2 Dylan Hartley (captain), 1 Soane Tonga'uiha.
Replacements: 16 Mike Haywood, 17 Alex Waller, 18 Tom Mercey, 19 Phil Dowson, 20 GJ Van Velze, 21 Martin Roberts, 22 Ryan Lamb, 23 Tom May.
Referee: JP Doyle
Assistant referees: Paul Dix, Peter Huckle
TMO: John Burtenshaw