Hearts will play Hibernian in the final of the Scottish Cup for the first time since 1896 after substitute Craig Beattie's last-minute penalty gave the Gorgie side a shock 2-1 win over his former side Celtic at Hampden.
A minute after the break Rudi Skacel raced on to a pass from Beattie, who had replaced Scott Robinson at the interval, to fire Hearts into the lead.
Four minutes from time Celtic striker Gary Hooper headed in a Charlie Mulgrew cross, but in the final minute referee Euan Norris dramatically awarded Hearts a penalty, when Marius Zaliukas' shot hit the arm of Joe Ledley, and Beattie scored from the spot.
Celtic and Hearts both passed up chances to break the deadlock in the first half of their William Hill Scottish Cup semi-final at Hampden.
Hearts striker Stephen Elliott was presented with a gift in the first minute when Celtic defender Kelvin Wilson underhit a back-pass but goalkeeper Fraser Forster blocked the shot.
Celtic responded but Mikael Lustig and Gary Hooper headed wide, Kris Commons failed to take advantage of an error by Hearts stopper Andy Webster and midfielder Ki Sung-yueng hit the post with a header from a Lustig cross with seconds remaining.
Celtic manager Neil Lennon made one change to his side for the clash.
Sweden right-back Mikael Lustig came in for Adam Matthews, who failed to make the bench.
The Tynecastle side showed two changes, defender Andy Webster and striker Stephen Elliott in for the injured Jamie Hamill and Gary Glen, who dropped out altogether, while former Celtic striker Craig Beattie started on the bench.
Hibs awaited the victors in next month's final and while the Clydesdale Bank Premier League champions were looking to take another step towards the double, Hearts were looking to set up the first all-Edinburgh final since 1896.
The Tynecastle side had a great chance after just 30 seconds when Celtic defender Kelvin Wilson was short with a back-pass which let Elliott in but his shot from a tight angle was blocked by Hoops keeper Fraser Forster for a corner, which ultimately came to nothing.
Hearts had six players in their starting line-up - skipper Marius Zaliukas, Rudi Skacel, Andrew Driver, Darren Barr, Danny Grainger and Scott Robinson - one booking away from missing the final. However, there were no signs of them holding back and there were some hefty challenges in the early stages as Celtic responded.
There was another moment of slackness from the Parkhead defence though in the ninth minute when defender Charlie Mulgrew was robbed by Jambos midfielder Ian Black who raced into the box but his pass failed to find Elliott.
Lustig headed a Kris Commons free-kick over the bar from six yards out five minutes later, before a fine Mulgrew cross into the box evaded Georgios Samaras, but the game was taking its time to come to the boil.
In the 21st minute Black was lucky to escape with only a booking after a challenge on Celtic midfielder Joe Ledley, in an incident which saw Mulgrew also pick up a yellow card.
Gary Hooper was presented with his first chance but headed wide from Mulgrew's left-wing cross.
It was largely a scrappy game but a great cross from the right by Lustig just after the half-hour mark, after linking well with Samaras, had to be turned away for a corner by Hearts right-back Ryan McGowan.
Moments later, Webster was short with a return pass to Jamie MacDonald, allowing Commons in, but the Scotland midfielder's touch was too heavy as he was forced to go around the Jambos goalkeeper and the opportunity was lost.
In the 38th minute, with Hearts retreating further, Black was penalised for handball but referee Euan Norris resisted the temptation to hand the Tynecastle hothead his second booking.
Celtic came closest yet to scoring in the final seconds of the half as midfielder Ki Sung-yueng hit the post with a header from a Lustig cross when it looked as if he must score.
HT Celtic 0 Hearts 0
Beattie replaced Robinson for the start of the second half as Hearts looked to pose more of a threat to Celtic and the move paid off after just a minute when the big striker helped Skacel fire the Gorgie side ahead.
After taking a pass from Black 30 yards out, Beattie quickly released Skacel into the box and the Gorgie midfielder rounded Forster before slamming the ball into the roof of the net as the past backtracking Mulgrew slid in to no avail.
Stunned Celtic immediately stepped up the tempo and moments later Ki fired over from the edge of the box with a drive which signalled a period of intense Hoops pressure.
However, Hearts were a threat on the counter.
In the 54th minute Skacel fired in a drive from 30 yards which Forster was glad to push round the post for a corner, which came to nothing, and moments later the Czech tried his luck from the edge of the box but this time his effort trundled wide.
Anthony Stokes replaced the ineffective Samaras on the hour mark as Lennon tried plan B but in another Gorgie counter-attack four minutes later, which left the Parkhead defence exposed again, Beattie fired wide from 20 yards.
Amid the growing tension, Stokes headed a Mulgrew cross over the bar before his low drive in a packed Hearts box was saved by MacDonald.
Beattie was causing all sorts of problems for the Celtic defence and he was the architect of one Hearts move which ended with Forster clawing Elliott's effort out from under the bar.
Victor Wanyama replaced Lustig before Denis Prychynenko came on for Elliott.
Ki hit the post again with a back-post header from Commons' free-kick in the 81st minute, before skipper Scott Brown made way for Dylan McGeouch.
MacDonald produced a fingertip save to stop Commons' free-kick going under the bar before making a great stop from Mulgrew's header with the rebound coming off Stokes' thigh and away from danger
But in the 86th minute Celtic eventually got through when Hooper headed in Mulgrew's cross from four yards out.
However, in the final minute referee Norris dramatically awarded Hearts a penalty when Zaliukas' shot hit the arm of Ledley and Beattie slammed in the winner from the spot.
