A Jamie Soward field goal seconds from full time has swept 2014's most-improved side to the final four, icing a come-from-behind 19-18 win over the Roosters at Allianz Stadium on Saturday night.
Panthers can dare to dream
Excited Panthers welcome week off
We've earned our second chance: Roosters
Robinson takes aim at refs after loss
WATCH: Soward kicks the winning field goal
WATCH: Full match highlights
WATCH: Panthers press conference
WATCH: Roosters press conference
Match stats, scores, highlights
As it happened: Relive NRL.com's live match blog
Behind by six points inside the final five minutes, a miracle try set up by Panthers skipper Soward, who nailed the clutch sideline conversion, drew the two sides level before Soward's high-pressure one-pointer sent western Sydney into raptures.
The win means the Roosters now face a sudden-death final next week against the Cowboys, while the Panthers get a much-needed week off to rest up and prepare for Melbourne, Canterbury or Manly.
Neither coach would have been remotely happy with their charges at half-time after a furious but error-riddled first half.
The Roosters completed just one of their first seven sets – and kicked it off with a cold dropped ball from Kane Evans in their very first set, finishing the half with a completion rate barely above 50 per cent.
The Panthers were almost as profligate, completing just 11 from 19, but after some ferocious early hits died down they managed to be first to score on the back of some Matt Moylan brilliance.
The gifted fullback took an attacking bomb on the fly around the 20 metre mark then found his way through the line to streak 50 metres. At the back end of that set a beautiful long cut-out from Jamie Soward created an overlap, with Jamal Idris doing enough to get winger Josh Mansour on the outside to score in the corner.
Showing precisely what not to do in the set after points the Panthers then came up with a simple mistake then conceded a penalty to invite their opponents down onto their try-line.
It's not the sort of invite the Roosters will need repeated and after heaping some pressure on the Panthers they cashed in through centre Michael Jennings, who made Will Smith look a level below first grade standard on his way to the line.
But after striking the crucial blow against his former club, the ex-Panther had to leave the field for a concussion check for a knock sustained in scoring the try.
The Roosters then showed exactly how you approach a set after points with a series of huge charges, followed by a towering bomb in attacking territory that earned them a repeat set, and then a couple more after that.
Penrith, to their credit, were able to absorb the mountain of pressure on this occasion and it was only Maloney's sideline conversion that separated the two sides in a half-time 6-4 scoreline.
The Roosters threatened to blow the game open after the break when a couple of big sets got them within range and a dummied flick-pass from Shaun Kenny-Dowall fooled the defence and Maloney's second sideline conversion made it 12-4 after 45 minutes.
Shortly after, there was a massive turning point when French prop Remi Casty was penalised for a double movement with the Roosters well in control and with all the momentum.
A try there would have all but put Penrith out of the game but instead a second penalty piggy-backed the Panthers into Roosters territory where Dean Whare received a perfect no-look Moylan pass before stepping through several defenders to make a jagged run to the line.
The scores were drawn level with 20 minutes to play when Mitch Pearce was penalised from in front and Soward took the two points on offer, setting up a grandstand finish.
With the field goal becoming an attractive option after a scoreless 10 minutes, Pearce pulled out a huge play when he set up for a field goal and elected to run, wrong-footing the defence, burning past Nigel Plum and pushing through Whare and Moylan to score next to the posts.
A missed field goal and potential seven-point lead from Maloney shortly after proved crucial.
Penrith needed a miracle to get back into contention and the footy gods duly provided.
With the side still 30 out on the last and time running out, a deft Soward grubber down the sideline looked to be headed into touch as Minichiello tried to shepherd the ball out of play.
But a determined Dallin Watene-Zelezniak chased it the whole way then leapt, with both feet in the air, to toss the ball back infield for Whare to dive on it. Soward's clutch sideline conversion made the scores level and when that ex-Panther Jennings fumbled a play-the ball just over one minute from time it gave the Panthers one last opportunity before golden point.
With 50 seconds on the clock they took a few tackles to get within range before the Roosters defence denied Moylan a clean shot. He smartly opted to take the tackle and from the next play the ball was fired back to Soward who had to take the shot from deeper than he'd have liked, but the 35-metre effort just scraped over the crossbar to send Penrith players and fans into delirium.
Penrith Panthers 19 (Whare 2, Mansour tries, Soward 3 goals, Soward field goal) defeated Sydney Roosters 18 (Jennings, Kenny-Dowall, Pearce tries, Maloney 3 goals) at Allianz Stadium. Crowd: 23.449.