Parramatta will face Melbourne in the NRL Grand Final after becoming the first team in history to qualify from 8th position.
Daniel Anderson's men defeated Canterbury Bulldogs at the ANZ Stadium in front of a non-Grand Final record crowd of 74,549.
Despite trailing 12-6 at the break, three second half tries from Luke Burt, Tim Mannah and Daniel Mortimer saw the Eels home, where they will face Storm, who are playing in their fourth consecutive Grand Final.
It continues Daniel Anderson's remarkable run of finals, having appeared in three Super League and three Challenge Cup finals during his time in the UK with St Helens.
Having finished 8th in the regular season, Parramatta recorded a superb 25-12 win over minor premiers St George in the qualifying finals, before their impressive 27-2 defeat of league runners up Gold Coast Titans in last week's semi-finals.
Melbourne meanwhile looked in ominous form as they thrashed Brisbane 40-10 at the Etihad Stadium in their preliminary final, which included a hat-trick from Greg Inglis and a double from Billy Slater.
It continues Storm's dominance of the NRL play-offs. They reached the Grand Final in 2006 where they lost 15-8 to the Broncos, and after finishing top of the table once again in 2007, they defeated Manly 34-8 to win the NRL.
Last season they claimed their third minor premiership, but were thrashed 40-0 by the Sea Eagles in a repeat of the 2007 final.
Parramatta were minor premiers in 2001 but lost the Grand Final in that year, 30-24 against Newcastle after trailing 24-0 at half time in what was their first Grand Final appearance in 15 years.
They also topped the NRL ladder in 2005, but were defeated by North Queensland Cowboys in the play-offs in the year the Cowboys lost in the Grand Final against Wests Tigers.
Last season, the Eels finished 11th and missed out on the play-offs, but under the stewardship of Anderson, they managed the top eight this season and would of course become the lowest ranked team ever to win the NRL should they defeat the Storm next Sunday.