Liverpool manager Jurgen Klopp admits it is difficult to accept that Jordan Pickford escaped punishment for his tackle on Virgil van Dijk.
The Dutchman underwent surgery on his anterior cruciate ligament after being injured by Pickford's tackle in the Merseyside derby on Saturday.
Thiago was also the victim of a rash Richarlison challenge in the 2-2 draw, and Klopp was surprised both players were not found guilty through retrospective action.
He told reporters: "A couple of days ago, something happened which for sure should not have happened in a football game. It's not the first time and it will probably not be the last time, but yes, I see it similar to my players. Both challenges were difficult to accept, let me say it like this.
"What we all can do is try to change these kind of things. It's really hard for us. Virg is our boy, and it has nothing to do with the quality of Virgil. Yes he's a world class player and we will miss him, but we miss Oxlade as well.
"Injuries happen in football, and very often in challenges, but very often both players try to play the ball, and that was not the case with these two challenges. That makes it different and makes it so difficult to take.
"The last four years, we were the leader of the Fair Play table. You don't get anything for that, in fact most often people make a joke about it and say 'Yes but you are not up there in the real table.' We were pretty high in both tables, which means you can play football without these kind of challenges."
Klopp then took at aim at referee Michael Oliver, who failed to punish either tackle during the game.
He added: "First the ref doesn't see it. Michael Oliver is an excellent referee usually but why he didn't see it, I don't understand because he had the best view.
"Then the VAR forgets the rules. As a human being, it's not that I want players punished, but if you do something wrong you have to deal with the consequences. At this moment, only one person deals with the consequences. Two, sorry. Virgil van Dijk and Thiago Alcantara. That's difficult.
"I wouldn't have spoken about it, but you asked me. You [the media] keep all these stories up. I am here to talk about a Champions League game, but you ask these questions and now everyone will judge us and say we don't deal with it in the right way, but we did nothing wrong in the game, and we are still the ones who suffer.
"That doesn't feel right and it's not easy to deal. We all accept that injuries can happen, but it should be in a normal challenge."