The decisive moment came from a set piece when Victor Osimhen helped turn a corner delivery into the danger area and Mario Lemina converted to give the hosts the only goal of the match.

Osimhen continued to torment Liverpool's defence throughout the contest and later thought he had scored himself in the second half, only for the effort to be ruled out following a VAR review.

Officials determined that Aydin Yilmaz had been offside in the build-up despite not touching the ball, a decision that sparked controversy. Osimhen had also found the net when the sides met earlier in the campaign, a 1-0 Galatasaray victory in September's league phase.

The latest result means Liverpool have now lost twice away to the same opponent in the same European season for the first time in major competition.

Liverpool struggled to create clear openings and were wasteful when opportunities did appear. Hugo Ekitike forced one of the few meaningful chances but struck straight at goalkeeper Ugurcan Çakir, while Florian Wirtz - making his first start since mid-February - scuffed two attempts on goal. The visitors' best chance fell to Alexis Mac Allister, whose shot drifted just wide.

Liverpool also had the ball in the net once, but the goal was ruled out after VAR penalised Ibrahima Konate for handball, a decision considered correct.

The match also marked the 100th game in charge for manager Arne Slot, though it proved an unhappy milestone. Osimhen's European goal tally this season is surpassed only by Kylian Mbappe and Harry Kane.

"There were a lot of similarities between three months ago and now," said Slot.

"We had multiple chances to score. After 10-15 minutes you expect us to lead and then their first attack leads to a set-piece goal. Last time it was a penalty. And another disallowed goal from us, so a lot of similarities."

He added: "You play two games against each other and now it's half-time, they're 1-0 up. We can do better, I'm 100% sure about that. But even with the game we've just played, we had enough chances to score goals.

"We didn't but next week we play at Anfield and our fans will be so supportive for us. I think that was today the situation for Galatasaray. They had great support from their fans, it was difficult for us to play in.

"Let's hope we can create the same atmosphere next week at Anfield."

Graham Potter's West Ham era begins with narrow FA Cup exit