The Special One is sure to get an earful from the Kop faithful, with whom he has had many squabbles over the years.
Reds' supporters will no doubt be revelling in the Portuguese's plight at Old Trafford; while United have bounced back from their difficult run of three straight losses in September, their most recent league outing saw them fail to beat lowly Stoke City at home.
SIGN UP NOW
That 1-1 draw led to renewed suggestions that Mourinho might have lost his touch, but that isn't a notion that's being entertained by Jurgen Klopp.
The German would look pretty silly if he were to insult his counterpart if United were to go and get a result, so he instead decided to launch a vehement defence of Mourinho.
As reported by the Guardian, when asked if he thought his new rival was past it, he responded:
“Who said this? Four people in Liverpool? It’s bull****. Rubbish.
"Who says this? He has started badly at United? They won their first games. So now you are giving B grades for winning?
“I try to play similar football now to my former team [Borussia Dortmund] and when we faced [Mourinho’s] Real Madrid it was unbelievably difficult to play them."
It genuinely seems like the two managers have a mutual respect for each other, even if they had a minor spat in the summer over United's decision to spend £89million on Paul Pogba.
To be fair, Klopp is basically saying what we're all thinking - Mourinho had a nightmare at Chelsea, and his start at United has been far from flawless, but it's way too early to write him off just yet.
“He has won the Champions League more times than I have played in it. That’s how it is," Klopp added.
It's nice to see at least one Premier League manager attempting to get on with Mourinho, but it might be a very different story after the game.
We'll see how long it lasts.
Is Jose Mourinho still at the top of his game? Have your say in the comments.