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 surprise 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 close the deficit to two points and give Hynes the chance to force extra time with his conversion.
From the right-hand touchline, Hynes struck his attempt well wide of the uprights and the visiting Dolphins consigned Cronulla to a heartbreaking defeat in Hynes' final Origin audition.
Coach Craig Fitzgibbon said the loss could not be blamed on a missed kick from his usually accurate star player.
"It'll get exacerbated, because it's him, of course. Everyone will talk about that," Fitzgibbon said.
"(The miss) will be tough on him. He's been working really hard with Daryl Halligan (on his kicking) and his numbers have been terrific all year.
"But I think it's unfair to put it on a goal kick when we give up 22 points in the first half. The answer is probably lying in our defence and lying in the first half, I reckon."
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.
Now, they've claimed their biggest scalp of the season in thrilling circumstances on the road.
"You can't afford to turn your TV off when the Dolphins are playing," Bennett quipped.
"It's just remarkable the way they can hang in there and get in front and come back and all the things they did there tonight. Pretty special."
Hynes came into the clash with plenty on the line, with a newly fit Mitch Moses threatening to usurp him as NSW's halfback on Michael Maguire's team sheet this Sunday.
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 caught out as his opposite man Kodi Nikorima ran riot.
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 all of his first four attempts at conversion, the last giving Cronulla the lead.
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.
