Adam Lallana also got a rare start and van Dijk was pleased with the commitment of his teammates.
He told BBC Sport: "It was very good. Most parts of the game were comfortable, we were very dangerous in behind. It was a well-deserved win.
"The players coming in were fantastic, it's good to see, we will need everyone in this long season. We have to use everyone and they all stepped up.
"Divock Origi was fantastic. A club record is great but we have won nothing yet, we want to go all the way"