Roberto Di Matteo admitted Albion were again their own worst enemy after the 2-0 defeat to Blackburn Rovers.
The Baggies started brightly and defended well until the 41st minute when Gabriel Tamas headed past the impressive Boaz Myhill.
Rovers’ lead was doubled a matter of seconds into the second period when Junior Hoillet waltzed past Tamas to fire an unstoppable 20-yard effort past Myhill.
Albion rallied late on but could not find a way past former England stopper Paul Robinson who made two excellent stops to deny the dangerous Jerome Thomas.
Di Matteo afterwards admitted another show of poor defending had cost the Baggies dear.
"I think we were good in the first half," he said.
"I don't think we showed enough in the second half to be able to get a point or three.
"We started really brightly and had some great chances.
"Unfortunately we went 1-0 down through a bizarre own goal, which there is not much you can do about.
"The defender misjudged his jump, got it wrong, and the ball ended up in our net.
"But we were still in the game and had a good chance to come back.
"In the first half they had a couple of long throws, which are dangerous and difficult to defend.
"But in general we defended really well in the first half.
"There's not much you can do about the own goal but we have to do better than that on the second goal.
"The way we started the second half was not good enough.
"It was bad timing.
"We talked about it at half-time to lock up certain areas of the pitch and we didn't do it after just two minutes out there.
"Then we were 2-0 down and it's a tough ask to comeback from that."
The Baggies were denied a clear penalty in the second half when Peter Odemwingie was fouled a yard inside the Rovers box in the 67th minute. However referee Mark Clattenbury inexplicably awarded Albion a free kick a yard OUTSIDE the penalty area.
The Baggies boss admitted big decisions against his side were now happening on a regular basis and costing the club points in their battle to avoid relegation.
"Apart from the referee, everyone else felt we should have had a penalty," he added.
"It's not the first time.
"I'm fed up with talking about this after games.
"It's happening almost on a weekly basis now against us.
"It's incredible!
"That would have given us a lifeline.
"It's a foul and a penalty.
"I don't know how he saw it outside the box.
"It was clearly inside the box - not even on the line.
"Against Manchester United it was a clear penalty and this one was a penalty.
"Within three weeks we've had two major decisions against us, which costs you points."