The Roosters started stronger on Friday night and had the first points when Robert Toia broke free of a tackle from opposite man Casey McLean.
But after Penrith's scramble defence stopped the centre short of a second try, the Panthers surged up-field through a Dylan Edwards line break.
Tom Jenkins then crossed for the Panthers' first try and the visitors never looked back, completely shutting the Tricolours out of the contest en route to a 40-4 thrashing.
Three of the Panthers' seven tries came from catching the defence out on the last tackle, with two others resulting directly from Roosters handling errors.
"A couple of errors on our part and we couldn't get it back under control and then we allow one try to turn into two, into three, into four," said coach Trent Robinson.
"It's a big lesson for us around, how do you play the style that you want, have things not go your way and then get back to that? We just couldn't get it back into control."
The Roosters had been considered pre-season premiership fancies and unveiled their first-choice spine against Penrith, with Reece Robson recovering from injury to make his club debut.
But the star-studded spine had limited chances to impose themselves given a 69 per cent completion rate and 7-3 penalty count on Friday night.
"That performance tonight is very disappointing," Tedesco said.
The highly-favoured Roosters have conceded 40 points twice, slumping to 1-2 to begin the new season, before they face struggling Manly in round four.
But the Sea Eagles are coming off the bye and will be itching for bragging rights over Daly Cherry-Evans, who faces his old firm for the first time since a messy off-season exit.
Tedesco said the Roosters needed to have more grit when things were going against them.
"You want to stay positive but we've got to get harder in those periods, especially against top teams like that, because they'll punish you," he said.
"We weren't hard enough in the second half. We let too many tries in, we didn't threaten them at all, so that was disappointing.
"We'll have to have a good look at ourselves for the quick turnaround next week."
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