Slot is taking over from the beloved and departed head coach Jurgen Klopp, who has taken a sabbatical from the sport.
Mac Allister has spoken to the Slot during the recent Copa America his nation Argentina won, but knows he will have to experience training sessions to get a full understanding of the new manager’s demands.
"Obviously it must not be easy at all to replace a coach like Jurgen who was there for almost nine years and at Liverpool is now a legend of the club," said Mac Allister, per Liverpool Echo.
"Jurgen's farewell was fantastic and he himself created a song for the new coach! And I think that will help him a little. I think Arne, thanks to Jurgen, has entered the club on the right foot.
"I had talks with the new coach during the Copa America, we talked a little about the club and about what I saw and so on. You can tell he's a very trained technician. He spoke to me very well.
"And I talked with (Argentina team-mate and Bournemouth player) Marcos Senesi who played for him at Feyenoord, and he spoke very well of him.
"So I think there is a lot of optimism about what this season is going to be like for Liverpool, beyond the fact a great manager like Jurgen has left us. We have a great group and we believe the new coach can help us achieve a lot of things.
"I came to Liverpool because I wanted to continue winning things and I felt it was an opportunity of being at a club that is going to fight for things."