But coach Ivan Cleary has warned the Panthers must improve if they are to keep their historic comeback season alive in next week's semi-final against Canterbury.
Talismanic halfback Cleary hoisted the Panthers back into Saturday's elimination final after a spirited start from a Warriors side roundly dismissed as finals cannon fodder.
The Warriors' season had sputtered following injuries to Luke Metcalf and Mitch Barnett, but the hosts never let their visitors breathe easily in greasy Auckland conditions.
It wasn't until centre Casey McLean iced a superb 80-metre team try that the Panthers looked on track, taking a 10-point lead in the last 15 minutes.
"It's a tough ask to come over here and play a final. The conditions were really difficult as well," said coach Cleary.
"We scored some tries that you could probably call opportunist tries but that's what semi-finals are all about.
"I feel like there's a little bit more in us, respectfully, and we'll need to play better. (But) I'm just happy to come here and compete and get the win."
The Warriors had been entrenched in the top four for 16 straight weeks this season before injuries hit, with coach Andrew Webster heartbroken to have bowed out in week one of the finals.
"We came here ready to go, we looked like a finals team, but we lost. That's why it's heartbreaking," he said.
"You lose a finals game, it should hurt. The moment it doesn't hurt, you probably shouldn't be here."
The winner of next week's semi-final will meet either Canberra or Brisbane in a grand-final qualifier.
Saturday's victory continues quite the run for four-time reigning premiers Penrith, who were last on the ladder after 12 rounds of the season.
They are now the only team in premiership history to win a finals match after being the bottom club so late in a season.
Cleary was on song against the Warriors, weaponising his kicking game to clinch momentum for the Panthers in the first half.
His side down 2-0 with 15 minutes before half-time, the 27-year-old made the gutsy decision to kick on the third tackle as the Panthers made a raid into enemy territory.
Paul Alamoti, replacing the axed Tom Jenkins, was outstanding and led the cover defence to lock Warriors fullback Charnze Nicoll-Klokstad in the corner of the field.
In the next attacking set, Cleary threw a cut-out pass for super-sub Isaiah Papali'i to score the Panthers' opening try.
Troubled by a groin injury earlier in the year, Cleary handed over goal-kicking duties to Dylan Edwards late in the game but saw the game out and continued to kick in play.
Deputising for injured hooker Mitch Kenny, Brad Schneider bolstered the lead after the break fooling Nicoll-Klokstad and Kurt Capewell to score out of dummy half.
"We were really good at absorbing pressure for so long in that first half then lacked some concentration," said Webster.
"The effort was there, it was just those moments letting us down."
But the Warriors were disciplined with the ball despite the conditions and struck back through rookie-of-the-year candidate Leka Halasima on the right.
The Panthers had a two-score lead after Cleary's bomb bounced away from Dallin Watene-Zelezniak and into the arms of a flying Luke Garner.
Blaize Talagi grabbed a suspect pass and kicked to the left, where Brian To'o continued the charge and put McLean over for a sparkling team try.
On return from two weeks' rest, To'o sealed the result scooping up an errant ball from Halasima and sprinting 60 metres to score.
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