There was no influence on Sadio Mane departure with Liverpool performance. I assess the absence of Diogo Jota, Thiago Alcantara, Konate due to injuries that have an impact on Liverpool because at the same time Liverpool also lost Darwin Nunez.
Jurgen Klopp certainly can't relax looking at the composition of his players when facing Manchester United even in the next few games such as against Newcastle who are good in 3 games.
Sadio Mané exit surely have no bigger impact on Liverpool performance, but sadly they are facing some serious injuries issue which can ruin their season because they lost few very important players and these are essential for them to have better replacement of these players surely Jota, Konate and Alcantara need to be fit as soon as possible but here we have some good thing now on this Saturday Liverpool is going to face Bournemouth which is just promoted, so now we can expect a win after three matches from Liverpool even they will be going with their second squad but Klopp will never take this risk, and he will go into this match with full squad and try to punish them for ending his frustration.
Liverpool's performance have dropped drastically, Sadio Mane was a key figure in the team and always came through for the team in very difficult game which they are currently lacking a player like that in the team. The absence of other first team players in the team also have an impact on the teams performance but I cannot ignore the fact that it would have been much better if they still had Mane in the team.