Ahead of Sunday's 2-2 draw at Arsenal, Slot discussed the leadership Van Dijk has shown around the club.
"I understand very well when people describe him as a leader," Slot told Viaplay.
"Because before I worked with Virgil, I always said I no longer believe so much in the concept of a leader. That is something from the past that people always talked about a leader in the team.
"When I played football myself, I always had Alfred Schreuder and Marco de Lofts. And Alfred is more famous than Marco. Who I experienced as leaders who really put us in place what we had to do.
"As a coach, I have never experienced someone as a real leader. For the longest time from a coach or something. But Virgil, I think, is someone who constantly makes sure the boys are there and is the leader in coaching."
"He also gives a good example of how to stand on a training field and what you have to do in the gym. And also, for the other players, by constantly standing up for himself."