Slutsky’s side led at the break thanks to Kamil Grosicki's fine 29th-minute strike but United turned things around in style in the second half to claim a 4-1 win, with Clarke leading the way.
He levelled in the 53rd minute before adding three more goals in the final 14 minutes to seal the victory and help United climb up to second in the Championship.
Hull's defeat was their third on the trot having gone down at home to Nottingham Forest and Middlesbrough in their previous two matches.
They are just four points above the relegation place and boss Leonid Slutsky admits he is worried about the situation, saying his team lacks mental strength and team spirit.
The former Russia coach said: "We are really broken after each goal. I tried to change the situation because in the last three matches we had the same situation.
"We concede a goal and we stop playing football. If we concede after 50 minutes, we stop after 50 minutes. Today we conceded after 55 minutes and we stopped after 55 minutes.
"Really, we don't have a strong mentality and we don't have team spirit.
"Of course it's very bad and I'm very angry. It's like two completely different teams playing before a goal and after a goal.
"I don't have the answer why. It's my job, I agree. It's not a question about somebody, it's about me.
"It is a very difficult time for me and of course I am worried. Now I have a lot of questions in my head and I don't have the answers. I will find the answers."