The Dutchman became the world’s most expensive defender after the Reds agreed a £75m agreement with Southampton last year, with the move coming into effect from January 1.
And, with Van Dijk having undergone his first few training sessions on Merseyside, Firmino admits he has been impressed with the defender’s abilities.
“He’s a really, really good defender,” Firmino told the club’s official website. “It’s always really hard playing against him. It’s very hard, he marks very tightly and I just think he’s a really, really high-quality player.”
“I think in addition to the fact he’s very physical, it’s his presence.
“He’s tall, he’s very strong and that’s in addition to his innate ability. I just hope he helps us as much as possible. I think like everybody else who comes in, they add something to the group and I hope that he can also do that and bring something to the team himself.
“I’m really looking forward to playing alongside him, of course. Obviously it’s great that he’s joined our team and now that he’s come with us of course I’ll welcome him in with open arms and I’ll look to make friends with him.”