The Senegalese forward appeared to snap a handshake from manager Jurgen Klopp after the game.
It is believed that the player was frustrated because Klopp decided to drop him for the crunch clash at Old Trafford.
The Liverpool manager decided to Diogo Jota in his place, and the Portuguese international justified his selection with a superb goal.
Mane was brought on in the final 20 minutes of the game, and he was unhappy with the coach’s decision.
After the game, Jurgen Klopp revealed that the player’s reaction is not an issue for him and that he should have explained the reason behind Mane’s exclusion better before the game.
Klopp said: “If somebody shows me five million times respect and one time not, what is more important? The world is then in the situation when it makes the one time bigger than is necessary. That’s, unfortunately, the case.
“I am completely relaxed about it. If you had seen me as a player and what I did out of emotion, it was insane, and I’m a completely normal guy. We will talk about it, and it will be sorted.”
Previously, there was a similar incident Involving club captain Jordan Henderson.
The Reds were held to a goalless draw at Old Trafford back in 2019, and Henderson was subbed in the second half by Jurgen Klopp.
The midfielder seemingly ignored a handshake and walked away from his manager, which prompted an angry reaction from Klopp, who demanded an explanation from the player as he made his way to the bench.
Later on, the Liverpool manager revealed that it was a simple misunderstanding.
The likes of Mane and Henderson are top-class players who want to play every week, and therefore their frustration is understandable when they do not get to play it as much as possible.
However, Klopp’s reaction suggests that the issue with Mane has been dealt with, and there are no issues between the two going forward.