The sloppy Dragons fell 44-12 down after 69 minutes on Saturday, only to come within inches of a miraculous comeback at CommBank Stadium that would have kept their top-eight tilt on track.
But with one last roll of the dice in the final seconds, Ben Hunt could not get boot to ball as he attempted a kick to his right edge and the Eels held on for the wildest of wins.
Flanagan refused to be swayed from his scathing critique by a Tyrell Sloan-inspired comeback that yielded five tries in the final 10 minutes.
"We can't be confused by only getting beaten by four points," the coach said.
"We were terrible, absolutely terrible. It looked like it was our first day together.
"It was a disgraceful first half. I apologise to the Dragons fans, sponsors, everyone. It was just not good enough. I've got to take ownership of that."
Asked whether he would consider making changes for next week's clash with Canberra, which the Dragons must win to have any hope of a fairytale finals berth, Flanagan reached the end of his tether.
"Unless I go to the local A grade and get some players, I won't be making any changes. I don't want to be rude, but I've had enough. Thank you," he said before standing up and leaving.
The result blows the top-eight race wide open; 30 points now set to be enough to clinch the remaining finals spot.
The Dragons had their finals destiny in their own hands at the start of the weekend, with wins in the final two rounds enough to guarantee their first finals appearance since 2018.
But now, even if they beat Canberra at home next week, St George Illawarra will need other results to fall their way to climb back into the top eight.Â
With everything to play for, the Dragons produced a woeful first half, winger Mikaele Ravalawa dropping the ball after the first tackle in a sign of things to come.
It took 14 minutes for the Dragons to play the ball in the Eels' half, such was their propensity for errors and inability to defend their tryline.
The Dragons went on to bomb three tries as they fell 26-6 down in the first half then leaked two further tries in the first two sets of the second half.
Sivo sneaks through to put Gutho over 👑 — NRL (@NRL) #NRLEelsDragons pic.twitter.com/qPt4X9tSQBAugust 31, 2024
Despite the shock result, Parramatta remain in a battle to avoid the wooden spoon when they face Wests Tigers next week.
Inspirational captain Clint Gutherson left the field in the final 10 minutes with a corked quad but insisted he was in no doubt for next Friday's "spoon bowl".
"I thought with eight minutes to go, we were probably safe and they decided to bring me off," he said sardonically.
In premiership history, no team had ever conceded 40 points and won, but the scoreboard did not faze the 16th-placed Eels.
"It really doesn't matter how you win, especially where we're sitting at the moment. You just want to win," Gutherson said.
Dylan Brown replaced Gutherson at fullback, having earlier put Will Penisini into a hole for the first try and looped a cut-out pass to Jake Tago as the Eels punished the leaky Dragons.
Hat-trick for Sivo 🎩 — NRL (@NRL) #NRLEelsDragons pic.twitter.com/EilMU7J6veAugust 31, 2024
Veteran winger Maika Sivo had his best game in recent memory, recording his 100th career try with the first of his three four-pointers.
