The midfielder made a major impact off the bench for Saturday's win against Burnley.
"I'm sure Harvey would love to be playing every week but at the highest level you have to be patient and grab your moments when you get them," said Van Dijk.
"He has to keep going. Don't be frustrated that you don't start sometimes, it is part of the business. When you get your opportunities, you have to perform and that's what Harvey has done in this case.
"Subs have made a big impact for us in games this season and this was another clear example. That definitely needs to be the case going forward as well."