Eels winger Maika Sivo scored four tries as the Panthers suffered a blow to their premiership campaign after star five-eighth Jarome Luai suffered a serious shoulder injury.
With their season all but over, Parramatta finished on a high with a 32-18 triumph in the derby clash before a sold out BlueBet Stadium crowd but Penrith were left with more to worry about than a rare loss.
The Panthers now need to beat the Cowboys next weekend and rely on the Broncos losing to Canberra or Melbourne to claim a third minor premiership in four years but of more concern is how long Luai will be sidelined.
The NSW and Samoa playmaker watched the final 53 minutes from the bench after reportedly dislocating his left shoulder trying to ground the ball for a try.
He was held up by Eels forward Bryce Cartwright and concerned players immediately called that Luai had suffered a serious injury.
Parramatta captain Clint Gutherson also failed to finish the match but he inspired his team to a fourth defeat of Penrith in their last six clashes before hobbling off in the 65th minute.
With the Eels having started strongly in their last two matches against the Storm and Roosters, but fading before halftime, coach Brad Arthur shifted Junior Paulo and J’maine Hopgood to the bench, alongside Shaun Lane.
The move paid dividends as Parramatta were leading 6-4 when Hopgood replaced Wiremu Greig in the 18th minute and he produced two offloads in the next set before Sivo scored his second try.
The Fiji star was awarded an eight point try after being hit high by rookie Penrith fullback Jesse McLean as he crossed in the corner and while captain Clint Gutherson missed the conversion he had a second kick from in front of the posts.
Sivo scored his third try in the 24th minute after Parramatta five-eighth Daejarn Asi combined with Gutherson and centre Bailey Simonsson to create room out wide for the rampaging winger.
Down 18-4, the Panthers were desperate to get back into the game and Luai appeared set to score when he burrowed for the tryline but was held up by Bryce Cartwright and immediately clutched for his left shoulder.
With Luai’s departure forcing a reshuffle as Jack Cogger shifted to five-eighth and hooker Soni Luke coming on as a replacement, the premiers were only just hanging on when Gutherson scored three minutes before halftime.
It was a blow from which Penrith would not recover and despite a notable lift in intensity when they started the second half, the game was effectively over as a contest when Gutherson crossed again in the 43rd minute.
However, Gutherson had been troubled by a knee injury all match and when he was unable to stop Nathan Cleary from racing through the ruck to score in the 66th minute he put his hand up to come off.
The Panthers scored two further tries through Liam Martin and Tom Jenkins but it was too little too late.
Source: NRL.Com