The German goalkeeper, 25, endured a nightmare match after he gifted goals to Karim Benzema and Gareth Bale as the Reds suffered a 3-1 defeat in Kiev in May.
Karius had collided with Sergio Ramos prior to the mistakes and Liverpool clarified after the final that he had sustained concussion, though the statement did not mention the tangle with the Real captain.
Ahead of the Merseysiders' first pre-season match, Klopp has spoken out about the incident for the first time, saying the concussion is the “explanation” for Karius' errors but not an “excuse”.
He told Liverpool's official website: “He was influenced by that knock, that is 100 per cent.
“What the rest of the world is making of it, I don’t care. It’s really not important what the people say. We do not use it as an excuse.
“Now people could think for us it is the explanation – and for me it is 100 per cent the explanation and that’s all.”
Klopp has also explained how he first discovered Karius may have sustained a concussion from a conversation with Germany icon Franz Beckenbauer after the Champions League final.
He continued: “After four days I got a call from Franz Beckenbauer, our Bobby Moore, our biggest football player who is a good friend of mine.
“He called me and said he came from a doctor, he told me: ‘Your goalkeeper had a concussion.’
“I said: ‘What?’ because in the game, from my position that situation is not very good to see: ‘Maybe there was contact or not.’ I told him immediately: ‘OK.’
“He said the doctor is the most famous doctor in Germany. I said: ‘OK, give me a few minutes, I have to fix a few things.'”
Karius is likely to feature as Liverpool kick off their pre-season fixture list against Chester on Saturday.