The Dolphins have held off fast-finishing Cronulla and confirmed a 30-28 upset win that looms as another blow to Nicho Hynes' hopes of retaining the NSW halfback jersey for State of Origin II.
With his Blues spot already under pressure after a quiet showing in game one, the Sharks No.7 was powerless to stop the Dolphins from surging to a game-defining 22-0 lead after 26 minutes on Thursday night.
But after Cronulla shifted right on their last set of the night, Sione Katoa crashed over to trail 30-28 and give Hynes the chance to send the game into extra time with his conversion.
Hynes, who had kicked well all night, struck his attempt from the right-hand touchline well wide of the uprights and the Dolphins held on at Shark Park.
The win over the second-placed Sharks helps affirm the Dolphins' top-eight credentials after a soft draw emboldened their critics on a 7-5 start to their second campaign.
Wayne Bennett's side had not defeated a current top-eight side this season prior to Thursday, and hadn't yet need to travel to Sydney through 14 rounds in 2024.
Now, they'll return from the Harbour City with their biggest scalp of the season.
Hynes came into the clash with plenty on the line as well, with a newly fit Mitch Moses threatening to usurp him as NSW's halfback.
But Hynes had a quiet night from an individual standpoint, despite the hosts' gutsy comeback.
He squandered Cronulla's only chance in the red zone as the Dolphins ran out to their early lead, passing to Sifa Talakai on the fifth tackle and watching as the second-rower knocked on.
Two of the Dolphins' four early tries came down Hynes' right edge, though he was not the only defender made to look foolish as his opposite man Kodi Nikorima ran riot early.
Hynes sent the flat pass to Royce Hunt that led the in-form prop to open the Sharks' account late in the first half.
But after that, Hynes was virtually unsighted on a comeback either side of halftime, other than to slot four from four conversions that helped the Sharks to their first lead after 53 minutes.
His fast-starting side down by two points, Queensland star Hamiso Tabuai-Fidow came up with a crucial individual try on return from Origin duty.
The Dolphins fullback fielded Hynes' bomb fewer than 10 metres out from his own line and danced away from five-eighth Braydon Trindall to begin a tear down the field.
"The Hammer" burst his way through the clutches of another four defenders on his way to scoring a 95-metre try that restored the Dolphins' lead, which they never surrendered.