The four-time reigning premiers had their wobbles at Allegiant Stadium on Sunday (AEDT) as they took their first steps without Luai and James Fisher-Harris - the two most important players they have lost in five years as NRL heavyweights.
But against a Sharks side tipped as genuine title contenders, early signs were that Penrith will be competitive as long as Nathan Cleary and Isaah Yeo are on deck.
"(I got a) few more grey hairs, definitely tonight, if you thought that was possible," said coach Cleary on his 54th birthday.
"There's enough rust in that performance to do that.
"Obviously when you lose players, you can talk about that or your can talk about the guys you still have. We have probably five or six players in our current team that will be Panthers hall-of-famers.
"If you've got that many players of that calibre ... you're still in a pretty good space."
Down by six points in the final two minutes of a game that featured several momentum shifts, Cronulla had one last chance to level the scores.
But on the fifth tackle, centre Jesse Ramien opted not to pass right to an unmarked Sam Stonestreet and found himself stopped short by a horde of Panthers.
Coach Craig Fitzgibbon was encouraged by the performance against a team that has beaten Cronulla by an average of 30 points in their last three meetings.
"It's a really good first hit-out for us. They're the four-time premiers for a reason," Fitzgibbon said.
"They just got too far ahead and knew how to close it a little bit better than us."
The Sharks had dominated a clunky Penrith in the opening stages and had the first try through Ramien thanks to a double-pump from Nicho Hynes, before Yeo came up with a big play.
On the last tackle and with Cleary out of play in the ruck, Yeo sized up wrecking ball recruit Addin Fonua-Blake and ran around him to the tryline at close range.
Only minutes later, Cleary threaded a pinpoint kick past the defence for a flying Izack Tago and the Panthers looked on top at 12-4.
Later in his Sharks debut, veteran Fonua-Blake would find his own try by burrowing through Dylan Edwards, Scott Sorensen and Yeo.
Braydon Trindall took on the bulk of kicking duties for the Sharks after off-season speculation as to how he and Hynes would share the playmaking load.
"That's the way game lands tonight on that," Fitzgibbon said.
"They'll share depending on where we land."
Trindall put the Sharks back into the game with a kick for Briton Nikora to score, and then sent a beautiful flat ball to Kayal Iro in the second half.
Cronulla looked their best attacking a makeshift left edge featuring Jack Cole, Luke Garner and Daine Laurie, who came on when teenage winger Casey McLean suffered a head knock in the opening minutes.
But the Panthers constantly found a way to strike back, with tries to wingers Laurie and Paul Alamoti a product of their well-oiled system when shifting wide.
Cleary had his hands on the ball again in the second half as the Panthers spread for another Laurie try that ultimately proved the difference.
Cleary would have sent a scare through the Panthers' camp when he keeled over in backplay following a heavy tackle in the second half but a trainer attended him and he played on.
"I assume he just got winded," coach Cleary said.
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