Their NRL playoff hopes were killed off by the Sharks at Kogarah, with Kiwi Shaun Johnson one of the stars in Cronulla's 22-14 win.
The Warriors' hopes nosedived in the final 10 minutes, when their 14-12 advantage disappeared.
Sharks lock Toby Rudolf smashed his way through four tacklers to score a 74th-minute try which sunk the Warriors. It was the first NRL try for Rudolf, a player the Warriors believed was heading their way in 2021.
And the Auckland-raised wing Ronaldo Mulitalo put the issue beyond doubt minutes later, flying into the corner for the match-sealing try which ensured the Sharks will play in the finals.
The Warriors will finish off the season with games against the Raiders and Sea Eagles, but are now out of the hunt despite a much-admired end to a bizarre season in which they had to camp in Australia.
Interim coach Todd Payten has turned things around, but the turn wasn't great enough. It was an at times brutal game, epitomised by the way outstanding Sharks forward Siosifa Talakai smashed Peta Hiku's attempted tackle away late in the game.
The tension was there, the quality often was not. But it was gripping stuff.
Sharks wing Sione Katoa, under pressure from Roger Tuivasa-Sheck, blew a 72nd-minute try chance from a Johnson grubber kick, as the Warriors put themselves in a position for victory.
Another great Hiku pass - a no-look reverse effort in a Josh Dugan tackle - had set up Adam Pompey for a try early in the second half.
Chanel Harris-Tavita's sideline conversion levelled the scores, and when he kicked a long, low 62nd-minute penalty the Warriors led for the first time.
Things took another bad turn for the Sharks when they were penalised in possession by referee Matt Cecchin, but they held on as the Warriors launched at the line.
The magic was nowhere to be seen for Hiku when he threw the ball away on the fifth tackle, the chance of the Warriors applying the killer blow lost.
Johnson dominated the first half with grubber kicks setting up tries to the Sharks wings Katoa and Mulitalo.
Johnson had been absent for three weeks, the new dad also dealing with an injury. Sharks coach John Morris handed Johnson the captaincy for the first time - with Wade Graham and Chad Townsend suspended - and his strong first half also included a try saving tackle on Harris-Tavita.
Cronulla were given plenty of assistance from the Warriors, who conceded a series of penalties early in the tackle count, and had a fairly scruffy first half themselves.
When Johnson landed a simple penalty goal for a 12-0 lead in the 35th minute, it looked as though the Warriors would have a small mountain to climb in the second spell.
But as against the Eels in the previous round, they found a way to get back into the game just before the halftime hooter.
Warriors captain Tuivasa-Sheck, who has found fantastic attacking form in recent weeks, set up a Jack Murchie try with a trademark step before curling a pass to the second rower.
At 12-6 it was definitely game on – but the Sharks finished stronger.
Sharks 22 (Ronaldo Mulitalo 2, Sione Katoa, Toby Rudolf tries; Shaun Johnson 3 goals) Warriors 14 (Jack Murchie, Adam Pompey tries; Chanel Harris-Tavita 3 goals) Halftime: 12-6