West Bromwich Albion boss Steve Clarke was left frustrated after their 0-0 draw at Stoke City.
And opposite number Mark Hughes conceded the Baggies were unfortunate after Charlie Adam escaped punishment for tripping the visitors' Youssouf Mulumbu.
Clarke said: "I think the two words for it are stonewall penalty.
"How the officials have missed it is beyond belief, but sometimes you get decisions and sometimes you don't. It is a decision that didn't come our way.
"If he had wanted to con the referee he would have gone down on the first contact.
"He managed to wriggle free of that. It is clear, whatever angle you look at it, it was a penalty.
"I don't think he meant to do it but he ran down the back of his foot. It was a clear penalty.
"I don't criticise the referee overall. You have to understand I am talking about one decision here where I find it difficult that between them they didn't see the penalty."
Hughes said: "They will feel a bit aggrieved with the penalty claim they had - it looked like it was a penalty.
"But we had similar complaints a couple of weeks back at Fulham. As the old adage goes, they even themselves out. Apparently."
