Luke Priddis, the only Penrith player with grand final experience, was their hero as they upset the odds to beat the holders 18-6 in the climax to the Australian season.
Priddis set up two tries and scored one as the Panthers clinched their first title since 1991, setting up a confrontation with the British champions next February. The hooker made the break for the first of Luke Rooney's two tries and the only score of a brutally tough and fast first half.
The strongly fancied Roosters looked to be taking the initiative for most of the second half as they started to force mistakes from a Penrith side running out of fit players.
Shannon Heggarty's try tied the scores and it took some awesome defence from the Panthers to steady the ship.
But then the Roosters' full-back, Anthony Minichiello, dropped a kick and from that possession Priddis found his way over the line from dummy half.
Six minutes from time, with the Roosters expecting a drop-goal attempt, Priddis threw a long pass for Rooney's second and the Panthers were home.
That denied Adrian Morley his chance to become the first Englishman since Malcolm Reilly 30 years ago to win back-to-back grand finals in Australia. He did not deserve to be on the losing side after his powerful contribution.
Sydney: A. Minichiello, Byrne, Cross, Hegarty, Walker, Fittler, Finch, Cayless, Wing, Catic, Morely, Fitzgibbon, Ricketson. Replacements: Crocker, Lomu, Robinson, Flannery.
Penrith: Wesser, L. Lewis, Girdler, Whatuira, Rooney, Campbell, Gower, Clinton, Priddis, Lang, Galuvao, T. Puletua, Sattler. Replacements: Ross, Waterhouse, Rodney, Swain.
Referee: Bill Harrigan (Australia).Reuse content