Allan Johnston shouldered responsibility after watching his League One champions suffer back-to-back defeats for the first time this season.
But the Pars manager could not resist having a pop at some players after their most dismal display of the campaign.
The Diamonds were quick to cash-in on a makeshift Dunfermline defence as first half goals from Marc Fitzpatrick, Dylan Mackin and Jim Lister left the Fifers with a mountain to climb.
It proved insurmountable and it is debatable whether the outcome would have been different had David Hopkirk scored rather than hitting the bar with the deficit still just one goal.
Johnston admitted: “To be fair I have to take responsibility for that. We changed it to three at the back.”
However, the boss added: “Even though we changed the system it was still really poor defending especially when you lose a goal in the first minute from a corner.”
The pattern was set when Fitzpatrick out-jumped a feeble Dunfermline defence to put the Diamonds ahead.
Mackin was then allowed to run through unchallenged to double the lead before Lister’s header exposed more dodgy defending from the Pars.
A re-shuffle was sufficient to prevent further punishment but the damage had already been done and Johnston added: “We’ve had a few boys missing this week through illness and injury and we didn’t really get the chance to work on the system.
“But in saying that there were still individual errors as well. All their goals came far too easily and I don’t think we were anywhere close to where we’ve been since the start of the season.”
Dunfermline bring down the curtain on a memorable season on Saturday when they entertain a Peterhead side who are still fighting for second place.