Ollie Watkins scored a first-half hat-trick as the Reds conceded seven goals in a game for the first time since 1963.
Liverpool's back-up goalkeeper Adrian had a night to forget as his mistake allowed Watkins to open the floodgates.
"The first goal had an impact, but it shouldn't. Adrian made a mistake but we conceded goals like this in the past. We lost the plot then," said Klopp.
"When Aston Villa won the ball, our protection was under average."
Despite a change of system and personnel after half-time, Liverpool still could not stem the flow of Villa exposing their high line as deflected goals from John McGinn and Ross Barkley and Jack Grealish's double rounded off a remarkable scoreline.
"We had still good moments but our good moments led to nothing and their good moments led always to a chance or a goal," added Klopp.
"They were flying and we were pretty open. All the things you should not do in a football game, we did tonight."
Liverpool are not in action again for another two weeks due to the international break, but they face a huge challenge on their return when they travel to top-of-the-table Everton in the Merseyside derby.
"Overall we're all disappointed, we shouldn't have lost with the numbers that we did but it's about sticking together and making sure it doesn't happen again," said Liverpool defender Virgil van Dijk.
kca/td