The Reds boss made five changes from Sunday’s victory over Leicester, including altering three of his back four, and paid for it with a first defeat at Anfield in 90 minutes since Chelsea triumphed there in September 2018.
It was Klopp’s heaviest loss in 137 matches at Anfield, the Reds’ worst since losing 3-0 to West Ham in August 2015, and the first time since data began to be collected in 2003 that they failed to record a single shot on target in a home Champions League game.
Even the return of Mohamed Salah after his positive COVID-19 test could not lift the side out of their torpor as second-half goals from Josip Ilicic and Robin Gosens ensured there would be no option for Klopp to rest players in both of their final two group games.
“We made five changes, it was very important we did that, and in the end it didn’t work out and that is part of the deal. I would do it again,” he said.
“[We had] no real rhythm, first half was not a good game at all, they were not good as well. We spoke about it but second half it didn’t look like it [would change] and that is why we changed early.
“A second before we could change they scored the first goal, in a space which we knew they tried to use and we couldn’t defend in that moment.
“We had better football moments but not good enough. If you don’t have a shot on target that is never a good sign.”
Victory over Ajax next week would still guarantee safe passage and with December’s schedule, Klopp will want to avoid the nightmare scenario of having something to play for with the final game against Midtjylland.
“If I would think like this then it would be great. It is tricky, sounds easy to beat Ajax but with all the challenges we face in this country on top of the normal challenges we face already,” he added.
“My concern isn’t that I think about Ajax; we go in a few hours to play Brighton. When this game is over we start to think about Ajax.”
Atalanta coach Gian Piero Gasperini, whose side were beaten 5-0 in the reverse fixture three weeks ago, hailed the win as the club’s most prestigious.
“Obviously this is something which will be written in the pages of history,” he said.
“They haven’t lost a Premier League game in 64 matches. This is perhaps our biggest ever victory in our history, certainly our most prestigious.
“We were more solid in defence this time around because the defence was better protected with more players in midfield.
“This is the solution we opted for as we thought it was appropriate for this game.”