Blues were beaten 1-0 by The Trotters at St Andrews on Saturday and Clark blamed poor defending for Matt Mills' 20th minute headed goal for the visitors.
"I think we deserved something," the Blues boss said after the game.
“But we gave away a really poor goal from a corner.
“You win so many games at all levels from set-plays and Matt Mills didn’t just have half a yard, he had a couple of yards.
“It was one of our experienced players he lost, as well.
“We are frustrated with that."
Blues also finished the game with just nine outfield players after goalkeeper Darren Randolph was sent off for a foul on Craig Davies and with all three subs having already been used Lee Novak was forced to take over the keepers jersey.
“The penalty decision and the red card was spot on," said Clark.
“They were both the right decisions.”
“The goalkeeper has got to come and make a decision, if he doesn’t the lad ends up having a one on one.
“It’s very much against the ‘keeper. He has got to make a quickfire decision if he feels he can get the ball.
“Davies was quite quick on it.
“The players kept going, even after that.
“We put a bit of pressure on. But it wasn’t to be."