'They won't stop us having our fun, especially when Brazil win!'

World Cup fever gathered steam across Brazil on Friday after the long-awaited opener went ahead without major hitches, although the lingering threat of violent protests and a late scramble in some host cities kept organizers on edge.

-Football World Cup

Brazil's opening victory over Croatia unleashed celebrations late into the night on Thursday, with fireworks and car horns echoing for hours in major cities while fans got into the spirit of the first World Cup on Brazilian soil since 1950.

-Points Table: Football World Cup 2014

Shopkeepers in Rio de Janeiro and Belo Horizonte cleaned up storefronts on Friday that they had boarded up for opening day, when several protests against the costs and alleged corruption behind the tournament broke into scattered clashes with police.

Brazilians are still unhappy about the $11 billion spent to host the Cup in a country with glaring inequalities that struggles to fund schools, hospitals and other basic services. But many are just as frustrated with protesters now trying to spoil the party.

"They won't stop us having our fun, especially when Brazil win!" said Pedro Ribeiro, 29, a businessman in Belo Horizonte who held a house party until the early hours to celebrate the 3-1 victory over Croatia.

"People have a right to complain. There are lots of problems in Brazil. But they don't have the right to be violent or to spoil the World Cup we've all been waiting so long for," Ribeiro said. "This party is only just beginning."

The first full-capacity game at Sao Paulo's World Cup venue went smoothly on Thursday except for minor hiccups. A partial outage of stadium floodlights and the late arrival of food at vending stalls did little to dampen the carnival atmosphere.

But questions still hang over the other cities hosting their first games on Friday.

In the northeastern city of Natal, pouring rain, striking bus drivers and lingering safety questions about the stadium have crimped the runup to the Mexico vs Cameroon match.

Temporary new bleachers only cleared 90 percent of a safety check on Wednesday, officials told Reuters, and inspectors were barred from entering the stadium on Friday while world football body FIFA prepared for the match.

"The new seats may be done, but we didn't have the access to give our final approval," said state firefighters' spokesman Christiano Couceiro. "Anything that happens today is the total responsibility of FIFA."

Natal resorted to using school buses and vans to keep public transportation flowing after a bus drivers' union voted to strike over a wage dispute.

To make matters worse, days of sunshine in Natal have given way to driving rain. Groups of Mexican fans heading to the game were forced to huddle under trees, while minor flooding at the stadium put some security scanners out of service.

Rain in Porto Alegre in southern Brazil also interrupted construction around the World Cup arena, which remains a muddy work site days before hosting France vs Honduras on Sunday.

Workers in Cuiaba were still scrambling on Friday morning to install carpets and air conditioning in the Pantanal arena just hours before the Chile vs Australia match, according to officials overseeing work at the site.

Across the country, however, Brazilians' famous hospitality and good cheer were already overwhelming the rocky preparations in the minds of visiting fans.

"It has been amazing, people have been so nice to us," said Alvaro Roman, one of thousands of Chileans who had flown or driven across the continent to see the game in Cuiaba. "Brazil is a magical place!"