He said: It's a shame because it has taken the shine off what was a fantastic performance from our players," Blackwell told the Yorkshire Post.
"I'm not after an apology, just some credit for winning the first leg.
"I don't know Phil Thompson personally and I have never really spoken to him in the past, but we were all left stunned by his reactions.
"He bad-mouthed everybody in our dug-out, including the apprentices who were left shocked and he even tried to stop the Liverpool players swapping shirts afterwards.
"I offered Phil my hand at the final whistle and he was reluctant to take it. He just kept saying 'wait until we get you back to our place'.
"I told him to be a bit more magnanimous. You can't be a sore loser in this game. We had invited him for a drink, whatever the result, but he never arrived."