Liverpool have left Swiss global Xherdan Shaqiri out of the squad for Tuesday's Champions League tie at Red Star Belgrade, saying they were uncertain over what sort of reception he would receive in the Serbian capital.
"The boys are very disappointed, I'm very disappointed and we have to do better".
Liverpool missed the chance to cement top spot in Group C after they suffered a shock 2-0 loss to Red Star Belgrade.
Liverpool midfielder James Milner told United Kingdom broadcaster BT Sport that Liverpool had problems "all over the field" in the first half and never properly recovered.
'Rome was a special atmosphere (last season) and we dealt with that pretty well.
Alisson could do nothing, however, as Marin swung in the corner and Pavkov rose above his markers to spark wild celebrations among the fervent 55,000 home crowd.
The Liverpool boss and his side travel to Belgrade, Serbia to take on Red Star in the competition's group stage.
Much is being made of the intimidating atmosphere that awaits Liverpool's players inside the Rajko Mitic Stadium but defender Andy Robertson has urged his team-mates to lean on their experiences away from home previous year.
Klopp isn't anxious about the safety of Shaqiri, rather he'd prefer to keep the narrative around football than politics.
Left-back Andy Robertson, playing nearly as an out-and-out winger after the break, saw a cross deflected on to the top of the crossbar, while Salah finally forced a save out of Milan Borjan, hitting a post with his next effort.
That was of little concern to Red Star's players, however, as they joined arms and took the acclaim of their supporters on the full-time whistle.
The tensions date back to the Balkan War, where Serbian forces initiated a conflict against ethnic minorities across Yugoslavia; Shaqiri himself was born in Kosovo.