Dundee manager Barry Smith accepted the blame as his side slumped to a 3-1 defeat against Aberdeen at Dens Park.
Niall McGinn's second-half hat-trick left them nine points adrift at the foot of the SPL table.
Smith said: "That's as poor as we've been all season. I've got to be honest about that.
"But I'll hold my hands up and admit that I got it wrong with my team selection.
"There were a lot of tired legs after the Celtic game so personally I should have looked at it.
"In hindsight, I should have changed it because it was a demanding game where the boys really put in so much effort.
"We want to win as many games as possible but we just didn't do enough today which was the disappointing thing.
"We've got another big games coming up at St Johnstone in midweek which we'll get up for and get ready to go again."