Mark van Bommel has stressed that Netherlands must improve if they are to be successful at Euro 2012.
Oranje beat Slovakia 2-0 on Wednesday after previously losing warm-up friendlies versus Bayern Munich and Bulgaria, but Van Bommel feels that they are not at the required level just yet.
"We are satisfied with the result, but our performance leaves room for improvement. We have to learn from the mistakes we made, because we can't afford those kinds of errors at Euro 2012," the influential midfielder said to SBS6.
"I think we are heading in the right direction, though. We were much more threatening on the wings, and that's also where the opener came from."
Wilfred Bouma and Wesley Sneijder both sustained injuries during the match at De Kuip, and Van Bommel hopes the duo will be back shortly.
"We already had [Joris] Mathijsen's injury, and now Wilfred and Wesley. Let's hope it's not too serious, because we need everybody this summer."
Holland start Euro 2012 with the match against Denmark on June 9, before taking on Germany four days later and Portugal on June 17.