David Fusitu'a, Ken Maumalo, Tui Lolohea, Shaun Johnson and Manu Vatuvei were all guilty of making crucial first-half mistakes on both attack and defence, and the trend continued in a dire second-half showing.
"Just too many errors," said frustrated coach Andrew McFadden.
"Not just offensively but defensively we had individuals make errors you can't make.
"We work so hard for our points and then just give up soft points and it's as simple as that.
"You just get found out and we have been found out in the last month.
"It's disappointing that our season's come down to it."
The Warriors enjoyed a perfect start to the game, with Vatuvei and Simon Mannering scoring while the only touch enjoyed by the Eels was a knock-on from wing Michael Gordon.
But with the Warriors possessing an unrivalled ability to swing from brilliant to terrible, they wasted little time in welcoming the visitors back into the game.
The nightmare began when Lolohea inexplicably lost possession on a kick return to allow Eels hooker Isaac De Gois to run in under for the Eels' first try.
The comedy of errors continued with Luke kicking the ball out on the full from the restart and shortly after, some unexpected scrum pressure forced a fumble from halfback Johnson, which gifted De Gois his second in two minutes to see the Eels draw level inside the second quarter.
A simple defensive misread from Maumalo then let Parramatta's Fijian-born Kangaroos wing Semi Radradra in for their third try to give his side a four-point lead.
Fortunately for the Warriors, Luke's running game provided a second-try for the ever-reliable Mannering and the hooker's third conversion put them back in front 18-16.
But the advantage was short-lived and from inside their own half, the Eels confidently worked an overlap to put Radradra away and fullback Bevan French backed up on the inside to score their fourth with Gordon's kick reclaiming a four-point buffer just short of the break.
The Warriors began the second-half lazily and a barging run from Eels centre Brad Takairangi provided the momentum for French to score again off the next play.
Some strong defence forced another mistake from Vatuvei and French found it all too easy to claim his hattrick with Gordon's kick shooting them out to a 32-18 lead with more than half an hour remaining.
The Warriors managed to bomb more chances of their own through more poor handling from Vatuvei and Jono Wright before rookie replacement hooker Nate Roache was cruelly denied a late score.
"It's just not good enough at this level," said McFadden.
"We've got a clear picture of where our vulnerabilities lie and individuals have a clear idea of where their vulnerabilities lie."
The Eels then twisted the knife when centre Michael Jenning's crossed in the dying stages with Radradra converting to seal a 22-point win and consign the Warriors to a 10th-place season finish.
Warriors 18 (Manu Vatuvei, Simon Mannering tries, Issac luke 3 cons)
Eels 40 (Isaac De Gois 2, Semi Radradra, Bevan French 3, Michael Jennings tries, Michael Gordon 5, Semi Radradra cons)
Halftime: 18-22
