|ESPNsoccernet: World Cup 2010|
Netherlands coach Bert van Marwijk is expecting an improved performance from his players when they take on Slovakia in the second round of the World Cup on Monday.
• Slovakia Blog: No pressure may help
Even though his team recorded their third triumph in as many games, Van Marwijk was furious with his side's under-par display in their 2-1 win over Cameroon on Thursday.
"We could have easily lost that game and that was surprising to me,'' Van Marwijk said. "I spoke to my players very clearly after the Cameroon game.
"We played less well when we are ahead and we seem to think that it's going to be easy. But in the last 16 you cannot afford that and that is what I said to them.
"We cannot underestimate any rival because otherwise we will be in for a surprise. You can always be surprised in football.''
Van Marwijk believes, despite the fact his team have conceded just once while scoring five times so far, that the Oranje have yet to show their best form in South Africa.
"I think that we made a good impression in our first two qualifying matches,'' he said. "But it wasn't spectacular football and we can do better. There is room for improvement.''
Slovakia stunned Italy 3-2 last Thursday in their final group game to send the reigning champions home. And Van Marwijk believes they are capable of causing further upsets.
"I think they are a very rigid and tough team,'' he said. "They don't have any big-name stars but they play solid football as they proved against Italy.
"They played very well against the Italians and I think it's going to be a difficult game. We must be prepared for everything and over the past few weeks we have practised penalties more than enough.
"I think my players realise where we are, what this game means and what they have to do. They are all very motivated but they have to really focus in order to get the job done.''
Van Marwijk is expected to leave Arjen Robben on the bench for the clash with Slovakia. The Bayern Munich winger only recently recovered from a hamstring injury and made his World Cup bow against Cameroon.
"Arjen played for 20 minutes against Cameroon,'' said Van Marwijk. "He trained well but I will have to wait and see how he feels tomorrow.''