Coach Paul McGregor took aim at an "unacceptable" effort from his St George Illawarra outfit after the Dragons failed to cement a finals berth, in a second-last round loss to Gold Coast.
The Dragons led 20-12 at halftime but a poor second-half effort allowed the resurgent Titans a 28-26 win on Sunday, with Super League-bound forward Dave Taylor starring.
Manly's 46-12 hammering at the hands of premiership leaders the Sydney Roosters on Friday night handed the Dragons a golden chance to seal their playoffs berth. But they blew it.
"We knew what was coming. We just didn't play any tough footy," McGregor said.
"We're not in the finals, yet. It's just not the standard that we set. It's not good enough.
"We're all disappointed because it's unacceptable. They know that, and we've got to build on it. Some games you win; some games you lose. This one we didn't win, but it hurts - it hurts everyone.
"We've come a long way in 12 months but, to lose it now, would be disappointing."
The loss means the Dragons have to beat Wests Tigers at ANZ Stadium on Saturday to finish in the top eight. A Manly win over Cronulla on Sunday, coupled with a Dragons loss and a 62-point shift in points differential would hand the Sea Eagles an unlikely finals spot.
Either way, it is hard to see the Dragons challenging for the title given their lacklustre effort against the Titans. They won't have it all their own way in the final round after the Tigers smashed a poor Warriors 50-16 on Sunday, with skipper Robbie Farah starring in his first game after being told he was unwanted for next season.
Brisbane held second spot on the NRL ladder with a 47-12 thrashing of South Sydney on Thursday night to open round 25. The defeat sent Souths down to seventh spot.
Cronulla leapfrogged Souths into the top four courtesy of a 35-28 win on Saturday over Parramatta.
Sixth-placed Canterbury's 20-18 win over Newcastle has come at a cost with Trent Hodkinson ruled out for the rest of the season due to a wrist injury.
Third-placed North Queensland learned how hard life will be without Michael Morgan after they failed to make a linebreak in their 14-6 loss to fifth-placed Melbourne.
Canberra host Penrith in the final match of the season's penultimate round on Monday night, in a fixture that has no bearing on the finals.