Van Dijk, 27, has been a key figure in Liverpool's challenge for the Premier League title and has been highlighted as the most important player in the team by Reds legend Sami Hyypia.
And Pochettino has been impressed by Van Dijk's influence at Anfield, saying Liverpool were right to spend big to get him.
"When a team like Liverpool need to improve their team in a certain area, people said it was crazy to pay £70m for a centre-back," Pochettino told reporters.
"But Liverpool were right. They picked Van Dijk, because at that moment they believed he was the best centre-back in England who could make them better, and they were right.
"Some people said, ‘Why would you pay £70m for a centre-back?’ But the people who believed other things have now been shown that Liverpool were right.
"If you are going to sign the player who is going to improve your team, then it is not a lot of money.
"Because when you consider what it means to win a Champions League or a Premier League, it is cheaper to spend this type of money."
While Premier League leaders Liverpool have benefited from investing in the squad with signings like Van Dijk, Pochettino has had to make do with the same squad he had last season.
Spurs have fallen 15 points behind Klopp's men ahead of their meeting at Anfield on Sunday and the coach is eager to see them bounce back from their run of four league games without a win.
"We have good players. We are good enough, but the problem is that if we are not playing like a team," he added.
"The first half against Southampton (2-1 defeat) was the perfect example. The first half the performance was good but in the second half we played 11 different games and what happened, happened.
"That’s what worried me a little bit and we need to recover our memories and our feeling that we need to fight altogether and we need to show the real quality altogether like a team.
"That is more important than the individual."