Scamacca broke the deadlock in the 38th minute after Caoimhin Kelleher allowed his low drive to creep under him.

On a deeply frustrating night for below-par Liverpool, Darwin Nunez missed two big chances, while Harvey Elliott's curling attempt struck the bar before dropping on to the post.

Mohamed Salah, who started on the bench, forced a fine save from Juan Musso after Kelleher had atoned for his error to stop the unmarked Teun Koopmeiners from doubling Atalanta's lead.

The Egyptian also had a goal disallowed for offside, but the Reds were flat and lacked urgency in their play - and were punished for some dreadful defending.

Scamacca - who had just one season at West Ham before joining Atalanta last August - took advantage of being left unmarked by doubling the lead with a crisp finish on the hour.

Pasalic's 83rd-minute strike came after Brazilian midfielder Ederson was afforded too much space to shoot and, when Kelleher made a save, the Croatian snapped up the rebound to score.

The winners of this tie will face Benfica or Marseille in the semi-finals, with Benfica establishing a 2-1 first-leg advantage to take to France next week.

Liverpool pay heavy price for poor performance

Liverpool 0-3 Atalanta: We deserved to lose - Klopp

Jurgen Klopp looked bewildered at the final whistle after seeing his side comprehensively beaten by Atalanta, who sit sixth in Serie A and trail leaders Inter Milan by 32 points.

The Liverpool boss, who made six changes to the side that drew 2-2 at Manchester United on Sunday, has enjoyed some incredible European nights under the lights at Anfield during his nine years in charge.

But this could well be the last time he experiences a European home game after his side were a poor second-best to a clinical Atalanta, whose players and management team celebrated in front of their jubilant travelling fans long after the final whistle.

Liverpool had been looking to put the disappointment of Old Trafford, and dropping two points in the title race, behind them.

Instead they are now fighting to stay in Europe after one of their poorest performances of the season - and a first home loss since a Champions League last-16 tie in February 2023 when Real Madrid beat them 5-2.

Even the return of Diogo Jota from injury after a two-month absence could not inspire the Reds, who were looking to establish a comfortable cushion to take to Italy before three successive Premier League away games inside a week.

But they never got going and Klopp's hope of ending his Liverpool reign at the Europa League final in Dublin on 22 May looks a distant dream.