Fielding a number of players from last year's NSW Cup and Jersey Flegg-winning sides, the Panthers showed their future remains bright with a grinding display earning the win.
The Eels controlled large portions of the game, and dominated territory at the BlueBet Stadium, but lacked killer impact in the last 20 metres.
Among the Panthers' stars was winger Jesse McLean, who celebrated his recent upgrade to the 30-man NRL squad with an impressive try, chasing down a loose ball and gathering his own grubber.
Of those on the field, only Jaeman Salmon, Zac Hosking and Sunia Turuva are expected to feature in the Panthers' round-one side, with Turuva set to fill in for winger Taylan May who is serving a two-game ban.
Turuva had a try assist while second-rower Hosking, who joined from Brisbane in the off-season, looked assured running for 50m.
Penrith's lineup featured just one player, Salmon, from their grand-final winning outfit, with the big guns expected back for next weekend's World Club Challenge against Super League champions St Helens.
Parramatta started with gun back-rower Shaun Lane and forward Ryan Matterson, who will sit out the first three games of the season through suspension.
Matterson was close to the Eels' best player, running for 115m, while former Wests Tiger Zac Cini made the most of his opportunity with 115m and two tries.
Headline off-season recruit Josh Hodgson - who tore his ACL in the opening minutes of the 2022 season with Canberra - played his first game for Parramatta but did not make much of an impact outside of throwing an interception that Penrith returned for a 95m try.
Panthers hooker Luke Sommerton opened the scoring with a dummy-half dash, while young centre Tom Jenkins sprinted the length of the field after picking off Hodgson's pass for a try of his own.
A delightful offload from edge forward Mavrik Geyer capped the scoring for Penrith, sending Logan Cohen through the line to cross easily.
The contest was far from high-quality, with errors littered throughout - including five in the first six minutes - with the sweltering conditions in Sydney's west wearing the teams down throughout.
