Clark called for a foul as he went down under pressure from Dzeko but Lambert felt he was grasping at straws and believes the Irishman should never have made such a blunder in a match which devoid of frequent scoring chances.
"I thought we played well enough in spells," Lambert told Sky Sports.
"We had a right good go at it and had one or two half chances such as when Christian had one cleared off the line. We gave them a game that's for sure but the goal was ridiculous.
"I don't think it's a foul. I know what Ciaran is trying to do but you don't take a chance like that when there are only two of you at the back. You can't make that mistake.
"But Clarky has been great for me. You've got to hold your hand up and come back strongly. Over the course of the season he's played to a really high standard. He'll certainly learn from it."