The former Manchester United boss backed the Reds as the best team remaining in the Champions League.
Liverpool currently lead the Premier League by two points over Manchester City, who maintain a game in hand on their title rivals.
And van Gaal says both are better than a team many see as the favourite to win the competition, Barcelona.
“People think Barcelona are the best but they are not. Manchester City and Liverpool are more of a team than Barcelona – and Liverpool are more of a team than City,” he told BBC.
“In my philosophy, the best team shall win but I hope for City because they play the best football.”
Van Gaal managed Barcelona from 1997-2000 before returning to the club for another stint from 2002-03.
Van Gaal’s last managerial job was his stay with Manchester United, a frustrating tenure that ended in 2016 just days after van Gaal won the FA Cup.
Despite not returning to the game since, van Gaal says he has had other offers, but he is also content with his legacy as it stands.
“I have a philosophy. I was convinced of it and by winning trophies in four countries, I proved the philosophy worked,” he says.
“But my legacy is bigger than just my results. I am also a relations coach, not only with my players but everyone in a club.
“It is not my image but I am very human in that way. At Manchester United there were more than 40 people in the performance department. The medical department, the fans. They all had a heart for the club. I went to work as an analyst at a game at Liverpool and the United fans were still shouting my name.
“I am proud people still like me. That is what is most important in life.”