Police clashed with striking subway workers in Sao Paulo while huge traffic jams snarled the mega-city even as fans booed the national team.
The scuffle in the metro station and a separate anti-government protest that gathered 3,000 people raised fears of more unrest when Brazil and Croatia open the World Cup in Sao Paulo on Thursday.
Police fired tear gas and swung batons to beat back strikers inside a central station after commuters tried to enter.
The strike, affecting millions of commuters, will continue for a third day Saturday after the workers´ union and their employers failed to reach a deal on a pay raise.