Sao Paulo partied late into the night on Thursday. From my hotel just off the Avenida Paulista I could hear the car horns and celebrations going on into the early hours. Any other country and you would have thought they had won the World Cup but the 3-1 defeat of Croatia was still a significant victory for Brazil.

Neymar’s post-goal celebration, running to hug coach Scolari and the rest of the bench, encapsulated the delight – and relief – felt throughout the country. Neymar was under huge pressure before the game, not helped by comments from Dunga, the man who left him out of Brazil’s 2010 World Cup, who Brazil expected him to deliver.

Neymar’s slender young shoulders may carry the hopes of a nation, but against Croatia, just as in last year’s Confederations Cup, he showed that he can handle the pressure. For Brazil, though, the problems lie elsewhere.

Marcelo, Dani Alves and David Luiz all showed great attacking intent against Croatia. Unfortunately, Thiago Silva was the only member of the back four who looked capable of defending. The right flank looked particularly vulnerable, with Ivica Olic a threat in the first half, sending a header wide and suppling the cross that Marcelo turned into his own net for the opening goal.

Brazil’s key figures are likely to be the defensive midfielders, Luiz Gustavo and Paulinho, who will be needed to cover for the more adventurous forays of Luiz, in particular. The defensive midfield is probably the most important role in any international side. Luka Modric and Ivan Rakitic were an ambitious pairing for Croatia, and it was a mistake by Rakitic that let in Oscar for Brazil’s third goal. Other teams are likely to be more cautious than Croatia.

Brazil were fortunate to win the penalty after Fred’s tumble fooled Japanese referee Yuichi Nishimura. Still, they deserved their victory but it was not as convincing as the scoreline suggests. There have been plenty of upsets in Opening Matches of the World Cup – Cameroon beating Argentina in 1990, Senegal shocking France in 2002 – but Brazil 2014 was not to be among them. Brazilians will be grateful for that, but they will know that their team must improve in the coming weeks.

Brazil’s opening win has placed many Brazilians in a dilemma. Can they celebrate their side’s opening win, while also supporting the ongoing anti-government protests? Judging by Thursday’s events, it seems they can.

There was a strong police and army presence at many points throughout my journey from Sao Paulo airport to the stadium. Anti-government protestors were kept 10km away from the stadium and the authorities did not hesitate to use force to break up protests – as members of a television crew from CNN, hurt while covering one such protest, will testify.

State President Dilma Roussef celebrated Brazil’s victory in the stadium’s VIP section but was roundly booed by large sections of the crowd before the game. She believes her political fortunes are inexorably linked to that of the national side, but it may not be that simple.