Liverpool travelled to Serbia to play Red Star Belgrade in their Champions League group game and were defeated 2-0 by an impressive home performance from Red Star.
Milan Pavkov opened the scoring when he headed in Marko Marin's corner. Pavkov doubled Red Star's lead before the half-hour mark when he scored a superb individual goal. Liverpool were stunned at half-time, and Klopp made changes immediately.
But they were unable to change the scoreline, despite dominating most of the second half. This was Liverpool's second away defeat in the Champions League this season and Red Star's first win overall.
The loss means Liverpool are in second place in their group while Red Star remained rooted to the bottom but closer to their opponents.
Here are the major talking points from the game in Belgrade.
#1 Liverpool's midfield was porous and weak
Jurgen Klopp deployed a midfield consisting of James Milner, Georginio Wijnaldum, and Adam Lallana, as the two Englishmen lined up as number 8's alongside a deep-lying Wijnaldum. Simply, put, this trio was shocking in Belgrade, especially in the first half.
Red Star were buoyed on by their crowd's support, and the energy was apparently too much for Liverpool. Their midfielders failed to win a single tackle in the first half, as the likes of Marko Marin and Milan Pavkov were having their way. Milner and Wijnaldum had been brilliant prior to this game, but their performances against Red Star did not reflect that at all.
The creativity on display was poor, and they were guilty of giving the ball cheaply on numerous occasions. Pavkov's second goal came because Wijnaldum surrendered possession meekly in the buildup. Klopp changed the system to a 4-2-3-1 in the second half, pushing Lallana ahead, but the change failed to deliver.
#2 The Red Star fans buoy their side to victory
Red Star had conceded 10 goals in their last two away Champions League ties, but the Serbian outfit is a different beast at home. Going into the tie, they had lost just one of their last 44 home games, which was against Arsenal last season.
The win against Liverpool was another impressive home performance, and the raucous fans played their part. Playing at the Red Star Stadium is one of the noisiest experiences a player can get, and Liverpool's team will testify to that. The home fans were up for it before the kickoff, hurling abuse at Liverpool at every opportunity.
Jeering and whistling was commonplace throughout the match, and it induced a panic in the English side, a panic which multiplied when Red Star scored their goals. It's safe to say that the Liverpool players now know how their opponents feel at Anfield.
#3 For all their summer recruitment, Liverpool's depth in attack is suspect
Liverpool's front three were sensational last season, but the problem was seen in their replacements, who were not quite good enough. This season, on paper the situation looks good. Adam Lallana and Daniel Sturridge are fit again, Divock Origi is back from a loan spell, and new signing Xherdan Shaqiri has looked promising.
Klopp gave starts to Sturridge and Lallana in Belgrade, but both looked off the pace. Sturridge missed a golden chance in the early stages and Lallana was loose in midfield. Shaqiri still looks like a good option, but he did not travel due to political reasons.
As the festive period approaches and the fixtures pile up, Klopp will surely have to rotate his squad. Mane, Salah and Firmino cannot play every game, and the whole squad will have to be utilised. Whether they can do the job remains doubtful at this juncture.
#2 Tough times for Trent Alexander-Arnold
Alexander-Arnold came to the fore last season, particularly in the two-legged quarter-final against Manchester City, where he quietened Leroy Sane and impressed in general. Joe Gomez's injury made it seem like Alexander-Arnold had cemented his spot, but that has changed in recent weeks.
Despite his athleticism and attacking inputs, Alexander-Arnold has been found wanting defensively this season. He was partly at fault for Arsenal's goal at the weekend, and he was taken off at half-time in Belgrade to be replaced by Gomez.
Gomez has emerged as a more assured and mature defender, and his versatility means that he's above Alexander-Arnold in the pecking order. Nathaniel Clyne can also fill his position which casts further doubt upon his starts. That being said, his potential and willingness to learn are clear, so odds are that he will bounce back strongly.
#1 Group C just got way more interesting
A win in Belgrade would have sent Liverpool to the top of their group with nine points, and qualification to the knockout stages would have been within touching distance. But their defeat coupled with Paris Saint-Germain's draw in Naples makes their group tremendously interesting.
Napoli and Liverpool are tied at the top with 6 points, followed by PSG with 5, and Red Star with 4. Liverpool's last two fixtures are against PSG and Napoli, and they will need at least one win to have a realistic chance of qualifying.
Both PSG and Napoli will play Red Star, but the game won't be straightforward at all, as yesterday showed quite clearly. The Serbian side will also be harbouring slim hopes of progressing. Numerous permutations will come into play, as the group will end with a nerve-wracking finish. As they say, anything can happen!