The Reds dispatched Chelsea to the tune of a 5-3 scoreline on Wednesday.
As the Blues suffered their latest defensive disaster, Carragher took aim at Kepa and his defence.
He told Sky Sports: "Chelsea won't go no further unless they change their goalkeeper.
"[Lampard] has done as much as he can, yes Frank's still in his early stages but those big signings can completely transform you as a team.
"I still think Chelsea need a defender, you see how many goals they've conceded. I think a lot of that is down to the goalkeeper being totally honest.
"You see a lot of centre-halves at Chelsea without seeing one really outstanding one, those are the areas that if they are going to challenge Liverpool and Man City they'll have to rectify in the summer.
"They are the worst team in the league defending corners. This is a massive problem for Chelsea.
"Yes, Werner is coming in and the lad from Ajax, there is talk of Havertz as well. It sounds great and it gets supporters excited but it means nothing if you don't sort out that back three and certainly that goalkeeper."