Atalanta scored twice in four minutes to deliver a surprise victory over Liverpool FC and blow qualification from Champions League Group D wide open.
This was their heaviest such defeat since August 2015 in the Premier League against West Ham under Brendan Rodgers (0-3).
A much-changed Reds side lacked fluidity and failed to have a shot on target at Anfield on Wednesday.
Off Day for LFC
Josip Ilicic and Robin Gosens struck for the Serie A side midway through the second half.
Mohamed Salah, returning to the side, had fired over with the Reds’ best chance in the first half.
The Italian outfit looked more likely to break the deadlock and did so when Ilicic poked beyond Alisson from Alejandro Gomez’s teasing cross.
The visitors doubled their lead four minutes later when an unmarked Gosens volleyed in from Hans Hateboer’s nod down.
Klopp’s side still remains top of the group and need one win from their final two games – at home to Ajax and away to Midtjylland – to qualify.
Liverpool FC lacked their usual intensity and even the arrival of Roberto Firmino, Diogo Jota, Andrew Robertson and Fabinho after 61 minutes failed to inspire any urgency.
Instead, they were deservedly beaten by an Atalanta side they had inflicted a 5-0 defeat upon earlier this month.