With Liverpool trailing Barcelona 3-0 on aggregate, the challenge of pulling off a comeback has become that much more difficult.
Liverpool forward Mohamed Salah has been ruled out of Tuesday's Champions League semifinal second leg with Barcelona, after undergoing concussion tests on Sunday.
Salah collided with Martin Dubravka's hip in an aerial battle in the 67th minute of Liverpool 3-2 win over Newcastle on Saturday, and was unresponsive for around five or six seconds, before being treated on the field for an extended period and eventually stretchered off.
He is understood to have watched the remainder of the game from the dressing room, with subsequent reports explaining that he would not play against Barça if he was revealed to have suffered a concussion.
The Egyptian has now been ruled out of the Anfield second leg by Jurgen Klopp, who explained in his pre-match press conference that Salah 'cannot' play on Tuesday.
The German tactician explained, as quoted by James Pearce of the Liverpool Echo, that Salah had indeed suffered a concussion, whilst also revealing that Roberto Firmino would be similarly unavailable.
He said: "Both Mo and Roberto are not available." Concentrating on Salah, Klopp revealed: "It's concussion so he wouldn't be allowed to play. We cannot do it."
Liverpool need a three-goal swing to stand any chance of progressing to the Champions League final on Tuesday night, but the task will be made even harder with a second-string attack, something which Klopp acknowledged.
He admitted: "Two of the world's best strikers are not available tomorrow night and we have to score four goals to go through - that doesn't make life easier."
In more positive news, the Reds boss subsequently explained that Salah, who is on course for a second Golden Boot in a row, would be fit for Sunday's final clash of the Premier League season against Wolves.