Plymouth Argyle manager Paul Sturrock was left dumbfounded by his side's defensive blunders as they crashed to a 3-0 home defeat to Derby County.
The result leaves the Pilgrims 17th in the Championship table and only five points above the relegation zone.
"You can't legislate for simple errors from the back four," said Sturrock.
"The back four has had to chop and change over the last three or four games and we've not been settled.
"The second goal should have been cleared. It's not cleared, then somebody else should clear it in the middle, and it's not cleared and it finished up lying in the back of the net.
"The third one people are falling over all over the place.
"I keep saying two things, it's simple in the game, if our front two can keep the ball and our back two can header it away, then you'll win more than you lose."