The official allowed the Reds to regain possession after a stoppage due to a head injury to one of their players, even though Forest had the ball prior to the stoppage.
Van Dijk sympathised, but said they were on the receiving end of a similar decision from Paul Tierney in the past.
He stated post-game: "I think it (the frustrated Forest reaction) was about the timing of it. There was a moment in the first half when exactly the same happened to us...
"I mean, I don't know. If you lose in the last minute it's never nice and I can understand it. We came here to win. To get the three points and we got that."
Van Dijk added on Liverpool's fourth win in the past two weeks: "We've definitely been tested, yeah. Physically, mentally. It has been a very good six days. It couldn't have gone much better.
We did everything we could and we got everything we could. Now it's time to rest a little bit and then focus on the European game (vs Sparta Prague on Thursday night)."