John Ward was furious with Colchester's second-half defending as his side threw away a half-time lead to go down 3-2 at Yeovil.
The U's, aiming for a third win on the trot, led at the break through Steven Gillespie but goals from Dean Parrett, loanee Lawson D'Ath and Andy Williams turned the game in the home side's favour.
Martin Rowlands scored a free-kick to reduce the deficit for the visitors in the closing stages after Kieran Agard had been sent off.
But Ward said: "As slick as we were in the first half we were as dull in the second.
"In the period between Yeovil's first and third goals we were really dull but then gradually found areas where we could get back into the game.
"Lightweight defending cost us the points. If you come away and score two goals you expect to take something back on the bus."