West Brom boss Tony Pulis blamed players 'switching off' at set pieces for his side's 3-1 FA Cup defeat at Reading.
Darren Fletcher had put Albion in front early in the second half before goals from Paul McShane, Michael Hector and Lucas Piazon turned the game around.
The first two Reading goals were headers from free-kicks and Pulis was frustrated by the defensive lapses that allowed them.
"The two set plays that we conceded - and we've been very good defending set plays this season - were poor and it wrestled the game away from us in many respects," he said.
"We still had two really great chances at the end which we've missed but credit to Reading and I hope they get a good draw.
"When you come to clubs like Reading or clubs in the Championship and lower down, the one thing they are very good at are set plays. You have to deal with it, you have to defend it.
"We did okay with it first half, we defended that well. We scored the goal and just switched off. I've seen the two goals and it's really people switching off, not doing their jobs. You can't legislate for that."
Pulis also revealed that Jonny Evans picked up an injury late in the match that will see him face a spell on the sidelines.
"I've picked a strong team and the disappointing thing is Jonny Evans coming off with a hamstring injury late on," he added.
"They get their third goal with Jonny off the pitch, he was behind the goal off the pitch when they scored. He's going to be out for a few weeks now as well."