Northampton Saints defied Salesi Ma'afu's red card and the weight of history to secure their place in the Aviva Premiership final with a 21-20 victory over Leicester Tigers in a bad-tempered battle at Franklin's Gardens.
The Saints overturned a 17-6 half-time deficit and shrugged off tighthead prop Ma'afu's dismissal for punching Tom Youngs to sneak into the May 31 showpiece.
Tries from George North and Tom Wood cancelled out Leicester's scores from Manu Tuilagi and Ben Youngs, as Jim Mallinder's men avenged their 37-17 Premiership final defeat to Leicester last season.
Northampton denied Leicester a 10th successive Premiership final and a fourth-straight victory against their east midlands rivals at Franklin's Gardens.
Not since 1988 have Leicester won four in a row at Northampton, and that record remains, as the Saints produced a startling comeback to clinch their second-straight Premiership final appearance.
Last season Dylan Hartley's red card left Northampton heartbroken in the Premiership final at Twickenham.
This time around the Saints shrugged off battling more than 20 minutes with 14 men, to produce a sucker-punch, last-gasp victory.
An engaging contest was marred by Northampton prop Ma'afu's red card, with Leicester's Vereniki Goneva, Dan Bowden and hooker Youngs all receiving yellow cards.
For so long Tuilagi and Ben Youngs thought they had guided Leicester to yet another tickertape event: Northampton's relentless horde had other ideas.
Samoa wing Ken Pisi failed a late fitness test for Northampton, still suffering ill effects from a shoulder complaint picked up in the 74-13 Wasps romp last weekend.
England Under-20s cap Tom Collins stepped onto the right wing, but it was the midfield juggernauts who elicited early gasps from an enthralled crowd.
Toby Flood opened the scoring with a penalty on 10 minutes, Leicester content to take the three after finding no penetration from several forays into the Saints' 22.
Kahn Fotuali'i threw a delicious dummy in a bid to sneak round a ruck into the left corner, only for Mathew Tait to scrag him into touch at the last.
Phil Dowson powered home after Leicester bungled their five-metre line-out, but there was to be no try - referee JP Doyle ruled an early lift by Northampton.
Saints won a second penalty and fly-half Stephen Myler stepped up and bisected the posts without issue to level at 3-3.
Northampton were level for all of a minute. Leicester bullocked through midfield, Flood set Tait stepping through traffic into the shadow of the posts, and quick ball allowed Flood an easy palm-off for Tuilagi to score.
Flood converted the game's first try to wrestle back the initiative before Myler doubled his and Saints' tally with his second penalty.
One driving line-out later, prop Logovi'i Mulipola rumbled towards the whitewash and Ben Youngs squirmed home as he marked his 100th Premiership appearance in jubilant style, with Flood adding the extras - despite being a man down due to Goneva's yellow card.
The visitors took a 17-6 lead into the break, an ominous portent given their recent dominance over the Saints.
Goneva's madcap quick line-out almost gifted Northampton a try on the restart: Leicester escaped, but not for long.
Bowden received a yellow card for his dangerous tackle on Collins, with the home support baying for red and Myler slotted the goal to cut Saints' deficit to eight points.
The Tigers' trademark cool threatened to evaporate, with passes dropping astray and kicks punted out on the full.
Northampton pressed and pressed, but tighthead prop Ma'afu twice punched Youngs squarely on the jaw in an off-the-ball altercation.
After lengthy deliberation Tigers hooker Youngs was sent to the sin-bin, while Ma'afu was sent off just ahead of the hour-mark.
Bowden then returned with Leicester once again stubbornly not conceding a try.
Goneva and Saints replacement Calum Clark clashed in touch as tempers boiled over, but no action was taken.
Leicester's impressive rearguard was eventually punctured when North capped a textbook line-out drive, with Saints finally over the whitewash. Myler's nerveless conversion cut the deficit to one solitary point.
The Tigers tiptoed back to 15 men with as many minutes on the clock, and replacement Owen Williams landed a penalty to extend the visitors' lead to four.
Northampton punted a routine penalty to the corner with four minutes to play, pressing for the killer score.
Somehow, it came: Leicester's gutsy defence finally breached when Burrell sent flanker Wood into the left corner.
Myler struck the post with his touchline conversion, to leave Saints 21-20 ahead with 30 seconds to play and the hosts played out the time, booted the ball dead, and delirium in the stands was matched by endless laps of honour.