The nations new to Euro 2016 are playing "the tournament of their lives" and making it difficult for the established powers so far, according to Germany boss Joachim Low.
Poland coach Adam Nawalka admitted his side were happy to allow Germany to dominate possession in Saint-Denis, while feeling his team were under little pressure against one of the tournament favourites.
Slovakia, Hungary and Iceland have also pulled off impressive results against the odds so far this tournament and Low believes a succession of closely contested games to date are down to the confident counter-attacking approaches being undertaken by the lesser lights.
"I don't know if that's a result of 24 teams entering but we see that the results are quite close," he said. "Many goals have been scored at the end of the game, like with France and Northern Ireland.
"The results are very close because of the teams who are participating for the first time - it's obvious; it's the tournament of their lives.
"They invest everything they have and do what they are good at. They defend and wait for their chance and counter-attacks.
"That's what you expected, that the teams would fight and invest everything
Given the unpredictable nature of the tournament so far, Low was hesitant over branding any one side as favourites, although he does feel his own side are among the frontrunners despite a shot-shy outing in the French capital.
"I think always in the group stage it is very difficult to predict who is the great favourite," he added.
"We've seen in the last tournament that sides who were not so strong in the group stage improved later on.
"France are a favourite, they have a great side, the Italians had a great opening game. Then there's us, and Spain are always another side in contention to win a tournament. There might be one or two other sides.
"From the knockout stage onwards, you cannot afford a bad day and then you need luck to advance. It is too early to predict who will get to the final."