The 2010 finalists have won all four of their games so far in Brazil, including a last-minute win over Mexico in the second round last weekend, but the Dutch coach was keen to play down the talent in his squad.
He told reporters: "I may have some news for you - the Dutch media did not expect that we would get this far either. Everything we are achieving now should be fantastic for the Dutch media, but that is not the issue.
"The issue is our own objectives, our goal. Our goal has always been to become world champions and we have already said we are a team which is very difficult to beat.
"We're not a great team, but a team which is difficult to beat. So far we have shown that and I hope we can continue that up to and including the final. That Costa Rica are considered to be a less strong team. That is by the media. That is not our words, we are not saying that."
If they win, the Dutch would face the winner of Saturday's other quarter-final between Argentina and Belgium in Sao Paulo next Wednesday.