It was a night to forget for the visiting Blues, with only results elsewhere keeping them outside of the relegation zone as they extended their winless streak to five league games.
Ings' first goal of the night came after only three minutes and Arfield nodded home just 17 seconds after the interval to leave Clark feeling dejected.
Asked if frustration was the overriding emotion, he said: "Frustration's a feeling you have when you think you deserve to get something from a game.
"Probably the word (I would use) is disappointing because we got what we deserved.
"We didn't play well enough in every aspect of the game. When you lose goals so quickly in each half it becomes a problem.
"It's by far and away our most disappointing performance of the season.
"I take the full responsibility, I'm the leader of the group and I take responsibility for it. We go and push ourselves forward, dust ourselves down and get ready for Saturday."