Karius made two mistakes as Liverpool lost 3-1 to Real Madrid in the Champions League final last night.
The German was at fault for Real’s first goal, rolling the ball out only for Karim Benzema to make contact and the ball roll into the net.
Karius also made a mistake for Gareth Bale’s second strike of the game, meaning Liverpool were powerless to come back.
The footballing world has rallied around the 24-year-old, who was visibly upset after the game.
And Karius has now taken to social media to apologise for costing Liverpool their first trophy since 2012.
“Haven’t really slept until now… the scenes are still running through my head again and again… I’m infinitely sorry to my teammates, for you fans, and for all the staff,” he said on Instagram.
“I know that I messed it up with the two mistakes and let you all down.
“As I said I’d just like to turn back the time but that’s not possible.
“It’s even worse as we all felt that we could have beaten Real Madrid and we were in the game for a long time.
“Thank you to our unbelievable fans who came to Kiev and held my back, even after the game.
“I don’t take that for granted and once again it showed me what a big family we are.
“Thank you and we will come back stronger.”
Meanwhile, former Liverpool star Ray Clemence thinks Karius may be scarred for life following his errors.
“He’s made two horrendous errors at vital times in the game and he has to live with that,” he said.
“He’s got the whole summer to think about it and when you make mistakes in massive games like that they will be with you for the rest of your life, because people will remember them and keep reminding you of them.”