The Reds are set to face La Liga heavyweights at the semi-final stage of Champions League competition.
Last season’s beaten finalists are taking aim at another continental showpiece, but have the most testing of two-legged ties to take in before arriving back on that stage.
Messi, who netted twice against Manchester United in midweek to dash the European dreams of one Premier League opponent, poses the most obvious threat to Liverpool’s ambition.
Van Dijk will be among those charged with the task of trying to contain the mercurial Argentine, and the Dutch defender concedes that a serious challenge lies in store.
“It’s going to be a great match-up for all of us.
“Obviously we’re very happy to be in the semi-final again and that’s the only thing I can say.
“It’s about doing it all together, it’s never one versus one, it’s never just me against a particular striker.
“It’s always us against everyone and I think that’s the only way we can defend well.
“It’s going to be very hard and I think he’s the best player in the world but we’ll see.”
Liverpool booked their place in the last four by easing past Porto, with a 4-1 victory away from home sealing a 6-1 aggregate success.
Klopp is now preparing for a first competitive clash with Barcelona, although a coach that is also chasing down Premier League title glory is not giving too much thought to a meeting with Messi and Co. just yet.
He has said of the Champions League tests to come: “We are in the semi-final, we play against Barcelona, you can imagine I don’t think too much about it.
“But I’m really happy about the fact that we play them. We will find things where we think we probably could use it or whatever, but on the other hand side, I don’t care.
“We are in the semi-final and we play on Sunday against Cardiff - that’s in my mind and will be in my mind 100 per cent when I wake up tomorrow and not how we play against Barcelona.
“We have enough time for that and we can watch so many teams who tried it already and maybe we find something.
“I’m looking forward to it, but not now.”