Liverpool suffered another injury blow with Brazilian midfielder Fabinho joining Virgil van Dijk on the sidelines after picking up a hamstring injury in the 2-0 win over Danish side Midtjylland in the Champions League.
Fabinho has been filling in for Van Dijk in the center of defense since the Dutchman suffered a serious knee injury in the Merseyside derby against Everton. Van Dijk is feared to be done for the season.
"It's exactly the last thing we needed," said manager Jurgen Klopp, after Fabinho limped off in the first half.
"He said he could have played on but no sprints, which doesn't help. We will know more after a scan but clearly it isn't good."
With center-back Joel Matip also ruled out with injury, Klopp brought on teenager Rhys Williams to partner Joe Gomez at the back at Anfield.
Klopp accepted that the Premier League champions were in a difficult period.
"It's a bit like in a marriage, there are good and bad times," Klopp said. "One hundred percent we have to stick together and fight harder."
Diogo Jota's second-half goal put Liverpool ahead before Mohamed Salah made sure of the points with a late penalty.
Group D leaders Liverpool now have a doubleheader against Atalanta, who came back from 2-0 down to draw 2-2 at home to Dutch side Ajax in Italy.
Elsewhere, holders Bayern Munich continued their perfect start to their title defense with a 2-1 win at Lokomotiv Moscow in Group A, while Real Madrid needed a late goal from Casemiro' to rescue a 2-2 draw away to Borussia Monchengladbach.
Real are bottom of Group B behind leaders Shakhtar Donetsk, who drew 0-0 with Inter Milan in Kiev.
Atletico Madrid came from behind to beat Salzburg 3-2, with Joao Felix grabbing their late winner, in the other Group A game.
Manchester City, led by Kevin De Bruyne, eased to a 3-0 win at Marseille in Group C.
In the same group Porto beat Olympiakos 2-0 in Portugal.
Fabinho receives treatment on the pitch for a hamstring injury. AP