Traore netted twice at the Etihad Stadium to hand the Citizens their second defeat of the season.
Liverpool's Dutch centre back van Dijk was dumbfounded at City's inability to seal a point at home.
Virgil van Dijk said he was "surprised" that Premier League champions Manchester City were defeated by Wolverhampton.
The Reds currently lead Man City by eight points at the top of the league table after Adama Traore scored twice at the Etihad on Sunday to hand Pep Guardiola’s side their second defeat of the season.
However, the Netherlands defender has warned his Liverpool teammates that they should not get complacent because of the gap between them and the Citizens as he expects their rivals to bounce back.
“I didn’t expect that, of course,” van Dijk told Sky Sports. “Everyone expected a difficult game for City, but City at home but it doesn’t happen much that they don’t even score one goal at home.
“A great performance from Wolves, you have to give credit to them but you know the situation, you can’t really say much about it.
“They will try to bounce back from it and until then we’ve just got to focus on our international football of course.”
The 28-year-old insists they need to improve further despite their brilliant start to the 2019-20 campaign.
"We tried last year and unfortunately Man City was just a little bit better,” van Dijk said. “So far we have been getting the points.
“There’s always room for improvement in our game and, what I said already before, I think we should just focus on the games ahead of us and don’t look at any gaps or any points difference between us and the others, us and City.
“There are a lot of busy periods coming up as well, obviously with December, January.
“Anything can happen still.”