West Brom manager Tony Mowbray pleaded to his side to tighten their defence after an injury-time winner saved them from dropping points against Colchester.
Rock-bottom Colchester, who are now all but doomed to relegation, took a two-goal lead after 16 minutes with goals from Chris Coyne and Medy Elito.
Albion were back on level terms before the break thanks to Chris Brunt and Kevin Phillips scoring his 22nd goal of the season.
Kevin Lisbie regained the lead for the visitors before James Morrison's last-minute equaliser and Roman Bednar's late goal earned Albion a dramatic victory.
Albion sit four points off the top of the table with two games in hand after the win but Mowbray is disappointed with his side's defending.
"Even though we have won the game my emotion is disappointment," he said.
"The way we are defending at the moment is a huge disappointment. I know we can't be successful and get where we want to go if we defend like that.
"There is a lot of work to be done on the training ground but we have been saying that all season.
"Going forward we can create problems. That is not a problem. The problem is when teams put the ball into our area. That is hurting us at the moment.
"It is great we stuck at it and I am delighted the players got the points but we have to keep the ball out of our net and then we will be a much better team."
Colchester manager Geraint Williams, who was sent to the stand by referee Graham Laws in the second half, was hugely disheartened that his side were left empty-handed.
"It is cruel for the players not to get anything after a performance like that which was full of passion and pride," said Williams.
"We didn't defend well enough and to come to a place like Albion, score three goals and not get any reward is criminal.
"We knew that West Brom would come at us in the second half but we put in a performance full of effort and it deserved some kind of reward.
"But West Brom keep going to the last. I hope they go up because I think they could have a chance to flourish in the Premiership with the way they play."