Tomas Ujfalusi has urged his Czech Republic team-mates not to get carried away following the 1-0 victory over Switzerland.
Vaclav Sverkos struck in the second half to give Czech Republic three points and put them on course for a place in the quarter-finals.
However, captain Ujfalusi is fully aware that Czech Republic cannot afford to be complacent after making a mess of a similar situation at the World Cup two years ago.
The Czechs made a dream start in 2006 with a 3-0 win against USA but then lost to Ghana and Italy without scoring another goal and failed to progress past the group stage after injuries to key players depleted the team.
"Of course we, know only too well that we mustn't rest on our laurels," Czech sports website www.sport.cz quoted Ujfalusi as telling reporters at the team's training base in Austria.
"We have to use what we learnt from the World Cup in Germany so that we manage our next games better."
Czech Republic face group favourites Portugal in their next match and Ujfalusi is anticipating a tough test.
Portugal impressed in beating Turkey 2-0 on Saturday but Ujfalusi thinks they will find it more difficult to get past Petr Cech.
"We are aware that behind us is one of the world's best goalkeepers," praised Ujfalusi.
"Whenever we defenders make mistakes or go to sleep, it is always him who protects the team. Immediately in the first game he did it twice."