The Reds conceded seven in a match for the first time since losing by the same scoreline to Tottenham in April 1963 while Arsenal were the last defending champions to ship that many goals when Sunderland beat them in September 1953.
Watkins opened his account since a big summer move from Brentford in style by netting three of them inside a crazy 40 minutes and by doing so he became the first player to score a hat-trick against Liverpool since Dimitar Berbatov in 2010.
John McGinn’s deflected first-half effort also helped Villa go into the break with a 4-1 advantage and further strikes from captain Jack Grealish (2) and a debut cracker from Ross Barkley saw them seal a landslide victory that nobody would have seen coming.
Klopp, who hit out at Sky Sports pundit Roy Keane last Monday after the former Manchester United captain claimed Liverpool were “sloppy” at times during their 3-1 win against Arsenal, said: “Last week Mr Keane said we defended sloppy, it wasn’t sloppy tonight it was just bad.
“Nobody to blame but us. If we can put all our rubbish mistakes in one game then it’s done and we can start again. I would love to have a training session tomorrow or on Tuesday. But the boys now go out with their national teams and I have to find the right words when they come back.
“I saw a game in which for different reasons Aston Villa did really well and forced all the mistakes we made, and then the game has a specific direction.
“The first goal had an impact but it shouldn’t. Adrian made a mistake for the first goal but we conceded goals like this in the past. The reaction was then, we lost kind of the plot. Our creating was really good but we did not score.
“We still had good moments but those good moments pretty much led to nothing, and their good moments led to big chances or a goal.”
Liverpool defender Virgil Van Dijk said: “It’s hard to lose the way we did tonight. You have to give Aston Villa the credit they deserve, but if we are looking at ourselves we felt it was one of those performances where we weren’t 100 per cent at it from the start until the finish.
“Now it’s key to stick together and make sure it doesn’t happen again. We have to be stepping up the performance level and everyone has to take responsibility.”
Watkins, who did capitalise from a horrendous early Adrian howler, told Sky Sports: “I think when the first one went in I pinched myself a little bit as it was so early on. I’m just delighted I could contribute and we won.
“It’s unbelievable, before the game I wouldn’t think I’d score three goals. But I got a bit of confidence and I should have scored more in the end. One-on-one with the goalkeeper, I’ve got to be scoring that.
“The game plan was to get in behind them. We fancied ourselves but we didn’t think the scoreline would be that.”