Brighton continued their dominance over Liverpool with a 2-1 win to dump the Reds out of the FA Cup.
The Seagulls defeated Liverpool 3-0 in the Premier League two weeks ago.
Harvey Elliot gave Liverpool the lead in the 30th minute from a Mohammed Salah’s assist.
Lewis Dunk equalised for Brighton nine minutes later to end the first half 1-1.
Fabinho escaped a red card for a dangerous tackle on Ferguson.
Kaoru Mitoma scored a 90th-minute winner with a stunning individual goal to send Britons to the fifth round of the competition.
Liverpool won both FA Cup and Carabao Cup last season, they have now been sent packing in both competitions in the fourth round.
Klopp has revealed that it doesn’t feel great to lose another game to Brighton.
“We came here after a game a few weeks ago when we weren’t even close to ourselves.
“Today we played a better game but we concede two goals from set-pieces and that is not allowed in any way.
“On the left side Robbo was ok because we helped him but on the other side Trent didn’t get the support.
“Mitoma is really good so, of course, it was tough.
“We could have defended both goals better.
“The first is deflected but we can probably block the shot.
“It doesn’t feel great. In time we might see the positives but we wanted to get the next round. Congratulations to Brighton.”
Up next for Liverpool is a trip to Wolves in the Premier League on Saturday.