Gloucestershire-referee Dunn issued a yellow card to the Spanish veteran Hierro after he had felled the Magpies flyer Kieron Dyer in full flight when seemingly through on goal.
Despite pleas by the Newcastle players to send Hierro off Allardyce says that Dunn got the decision spot on thus offering a reprieve for the ex-Real Madrid man.
"The referee got it right. There were enough defenders there not for him to be deemed the last man. My main worry was that it might have been a penalty but it was just outside the box." he said