The visitors went to Hull and back
on an afternoon to forget for Clark as The Tigers roared their way to a 5-0 lead.
Goals from Peter Lovenkrands and Chris Burke late on softened the blow slightly, but the Blues boss was still left to reflect on basic errors from his side.
Clark said: "Without taking anything away from Hull, who were rampant, I think we could have done something about all of the goals. Certainly the first three, which took the game beyond us, weren't particularly well worked goals.
"I have no complaints as we got what we deserved today. Even at 0-0 this is a tough place to come and play with the way they play the game and move the ball around. We didn't give ourselves any chance to get a foothold in the game.
"The goals have come from errors of our own. It wasn't the formation or the tactics, it was decision making and individual errors.
"We've had two clean sheets on the bounce and been strong away from home. We've usually come away, been solid and nullified the threat of the home team to frustrate their supporters but it was party time for the Hull fans from an early stage.
"It wasn't a good day for us, we were very disappointed by the performance and the result."
With Blues already trailing 3-0, captain Steven Caldwell was substituted for Paul Robinson in the 37th minute of the match.
Clark revealed post-match that his skipper had been struggling with illness beforehand - and had since beat himself up for his part in Blues' early downfall.
"Stevie didn't feel right, he felt a bit of an illness," Clark explained. "He's a great man, he's a good leader and he's got that characteristic where he'll try to go out when he's not at 100 per cent. He's tried that today and unfortunately for him it didn't work.
"I said to the players at half-time that it was up to us to try to get out of the situation that we found ourselves in and help Stevie because he's done it for us many times this season but unfortunately it didn't happen.
"The big man has held his hand up but we win together and we lose together."
Clark is keen not to dwell on this recent defeat for too long and has urged his players to turn their focus straight to the visit of Blackpool on Tuesday night.
"I've said to the players to let me be down in the dumps on the journey home and let me analyse the game.
"They've just got to forget this and come in tomorrow, dust themselves down and be ready to go on Tuesday. We have two big home games coming up and we have to try to take maximum points off those two."