Notts County trounced Colchester to register back-to-back wins under manager Shaun Derry.
County went ahead through Jack Grealish, who fired past goalkeeper Sam Walker following Jamal Campbell-Ryce's low cross.
They doubled their lead when Morgan Fox slotted home from close range from Callum Ball's cross.
Callum McGregor and Gary Liddle then sealed victory for the Magpies in the final five minutes with late strikes.
VIEW FROM THE DRESSING ROOM
Colchester United assistant manager Mark Kinsella told BBC Essex:
"Very disappointed. Obviously everyone expects you to beat bottom of the table when they come to your home ground. We did our homework on Notts County and unfortunately they are not as bad as they look.
"Once they go on the pitch it's down to the players. We've gone through it all, we've gone through them individually and as a team, the way they play. It's very disappointing when we don't put what we worked on [in training] on Saturday at three o'clock.
"We knew their main threats and we thought we'd dealt with them.
"We both (Joe Dunne and I) know the club means a lot. Performances like this don't help anyone. It hurts us as well as the players when we don't perform."
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