Justin Holbrook's Newcastle revival has reached a preliminary final after the Knights defeated the Warriors 12-10 at Auckland's Eden Park on Sunday.
Newcastle will meet Penrith at Accor Stadium next Sunday, reaching the stage for the first time since 2013.
The undermanned Knights overcame a strongly pro-Warriors crowd, scoring through Fletcher Sharpe and Dominic Young while missing their first-choice front row and prized playmaker Dylan Brown.
Sharpe's early effort was disallowed, but the five-eighth soon created the opening try after Bradman Best broke through and supplied an inside pass.
Newcastle led 6-0 before Warriors centre Leka Halasima crossed in the 12th minute, leaving the teams level at halftime.
Dane Gagai then released Young with a flick pass after a forced error, and Sandon Smith's conversion gave the Knights a 12-6 advantage.
Halasima's remarkable 70th-minute finish revived the home side, but Tuaupiki missed the sideline conversion and Newcastle survived a tense final period.
Captain Kalyn Ponga and teammate Taine Tuaupiki both underwent head injury assessments, while Ali Leiataua was placed on report for a high tackle on Ponga.
Holbrook guided Newcastle from the 2025 wooden spoon to seventh this season and is considered the leading Dally M coach-of-the-year candidate.