But now I know a concussion isn't coming and going in a day - if you have one, you see it days later.
The goalkeeper had been elbowed by Sergio Ramos prior to his first mistake, and tests after the final found that he displayed 26 of the 30 signs of concussion.
Although a quintet of their stars are still involved in the World Cup, Liverpool reported back for pre-season on Monday, with new signings Fabinho and Naby Keita joining those uninvolved in global duty this summer.
"They come back before the tour to America - the 20th, I think".
That might have been because England were busy making it to a World Cup semi-final by beating Sweden 2-0 in Samara. So, from this point of view, from my side everything is fine. It's really not important what the people say.
"We are in July, we started the preseason previous year in July, so for 12 months these boys have had three weeks off. 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". Is he capable of parking that up, moving on and drawing from the experience?
"First half, I was not happy, of course".
He added: "I am convinced that Cho Hyun-woo will be a good choice for Liverpool". If you make a mistake in a Champions League final, it's a mistake you can not change anymore, even if you want to - and we all want to.
While Karius shrugged off the knock and got back to playing, he would inexplicably gift Real Madrid the opener and things continued to unravel for the Reds as substitute Gareth Bale got himself a brace thanks to some suspect goalkeeping. Still, overcoming such a devastating game in Kiev will be a massive challenge for the stopper, whether his performance was hindered by concussion or not.
"He is young so we don't want to bin a good goalkeeper because he does have the potential to be very good".