Liverpool had a night they'll want to forget in Belgrade on Tuesday night - but it won't be easy to do so.
Despite being huge favourites for the tie with Red Star, especially after their 4-0 win at Anfield two weeks ago, Jurgen Klopp's side struggled all over the pitch.
They conceded from a corner on 22 minutes after Milan Pavkov rose highest to head the ball home and the Red Star forward doubled his tally just seven minutes later.
Pavkov practically walked through Liverpool's midfield, brushing off the challenge of Gini Wijnaldum as Joel Matip backed off him.
His strike from outside the box was brilliant though, smashing into the back of the net and giving Red Star the two-goal cushion they needed to see out the game.
Klopp made changes at halftime but in truth, Liverpool never looked like turning things around.
They've now lost their position at the top of Group C in the Champions League ahead of fixtures with Napoli and Paris Saint-Germain; their situation in Europe is now a lot trickier than it should have been.
But while that's certainly not good, many fans have noticed a trend that's a lot more worrying.
Since Klopp's assistant, Zeljko Buvac, left the club last April, Liverpool's record in the Champions League has taken a nose dive.
Buvac walked out after a Premier League game with Stoke City - mere days before an away trip to Rome for a Champions League semi-final.
Before that game, Liverpool's record in the competition was 11 games, seven wins, four draws, and no defeats.
They'd lose 4-2 to AS Roma, however, and now their record without Buvac reads six games, two wins, and four defeats - a clear downturn.
In fact, Liverpool have now lost all four of their Champions League games away from Anfield since Klopp lost his assistant.
And you can see how worried the fans are:
The trip to Paris in the next round will certainly be an interesting one for Liverpool - they won't get many better places to prove that this record isn't anything to worry about.
There's still everything to play for in the group but Klopp simply can't afford another performance like Tuesday night.
If it does happen again, you can expect Buvac's name to pop up once again.