Liverpool supporters have been pretty downbeat in the last few hours after seeing their team suffer a surprise defeat in the Champions League to leave their qualification hopes in the balance.

Jurgen Klopp’s men went into their clash with Red Star Belgrade on Tuesday night top of Group C having picked up six points from their opening three matches, and thus were in a healthy position ahead of their trip to the Serbian capital. Yet the Reds produced a very poor performance to go down 2-0 on Tuesday thanks to a brace from Milan Pavkov, thus leaving the Merseyside giants second in the group with clashes against Napoli and Paris Saint-Germain to come.

As such, there have been many disappointed Liverpudlians up and down the country in recent times, several of whom have taken to Twitter in recent times to slate the move made by manager Klopp at half time to make a double substitution, in which he brought Joe Gomez and Roberto Firmino on for Trent Alexander-Arnold and Daniel Sturridge.

And while those particular calls were somewhat questionable, given it left the hugely ineffective Adam Lallana on the pitch, it wasn’t just at half time in which Klopp made a big error, what with the manager only making a handful of changes to the side that played an intense match against Arsenal a matter of days earlier.

Ultimately, the Reds put a lot into their 1-1 draw with Unai Emery’s Gunners at the Emirates Stadium on Saturday to suggest that several of those that started that match were likely to be mentally and physically jaded after such an intense battle, and while Klopp did make three changes to his starting line-up, it’s arguable that it simply wasn’t enough.

Obviously, it’s easy in hindsight to make such a judgement, but Klopp has until this point done a fine job this season of rotating his squad and keeping them fresh for every match they play - but they were certainly lacking that sharpness we’ve all come to expect from the Reds in recent times.

The likes of Mohamed Salah and Sadio Mane simply didn’t carry the same attacking threat seen from the duo in recent times, while even James Milner had an off-night to suggest that maybe he may have benefited from a rest - Naby Keita was on the bench on Tuesday night, yet didn’t play a part at all at Arsenal at the weekend.

Additionally, Alexander-Arnold has endured a testing run of form in recent times, which culminated in a very poor display against the Gunners on Saturday, and the England international again looked off the pace against Red Star to suggest that he also may have benefited from time out of the side - there's a reason he was hauled off at half time by Klopp in a decision which was perhaps the right one.

After all, it was certainly an off-day for a Liverpool side that have still made a very bright start to the new season, and as such there shouldn't be too much of an overreaction, but one wonders whether Klopp got it right to begin with in making so few changes to the team that produced an intense display against Arsenal at the weekend - add in that Alexander-Arnold and even Salah haven't quite been at their best recently, and maybe more changes should have been made.

So while those Liverpool fans were right to call into question his substitutions at half time, it wasn’t the only error Klopp made on what proved to be a desperately disappointing night for the Merseyside heavyweights.

Liverpool fans… what do you think? Let us know!