Brawling fans, acts of drunken vandalism and the sight of supporters being dragged off to police cells have marked the start of Euro 2008, prompting fears of more problems to come on Sunday.
Though the numbers involved were limited, the appearance of football's uglier face so early at the tournament in Switzerland and Austria will be a disappointment to organisers.
The football fared no better for the Swiss, who were beaten 1-0 by Czech Republic on Saturday and had their best player, striker Alex Frei, ruled out of the finals on Sunday after damaging knee ligaments in their opener.
Austrian police said 17 people were arrested overnight in Klagenfurt, which is the host city for Germany's opening Group B game against Poland on Sunday.
Known hooligans were involved in the brawls, an ominous echo of the trouble that erupted when the teams met in the 2006 World Cup hosted by Germany.
Police are expecting more trouble for Sunday's game, with potentially violent fans from Germany, Austria and Poland known to be heading there, according to Austrian police.