RIO DE JANEIRO, June 10 -- Victory for Brazil in their World Cup opener against Croatia on Thursday is vital to the team's chances of wining football's most coveted trophy for a sixth time, according to Selecao boss Luiz Felipe Scolari.

The 65-year-old warned his players could ill afford to trip in the Group A clash at Sao Paulo's Itaquerao stadium due to the resultant pressure in later matches.

"We need to win the first match to allow us to possibly slip-up in the second or third and still progress (to the knockout phase). Our tactical work has come a long way. There is little more to do before the first match."

For Brazil, Thursday's clash will be followed by fixtures against Mexico on June 17 and Cameroon six days later.

Having slipped to 22nd in the FIFA world rankings in June last year, the Selecao are now third following 15 victories from their past 16 matches.

Included in that run was last year's Confederations Cup triumph, sealed with a 3-0 demolition of world and European champions Spain in the final.

But Scolari refused to bask in past glories as he underlined the importance of a positive start in Sao Paulo.

"What worries me is Croatia," Scolari said. "It's important that we start the match well and pressure the opposition from the outset.

"When we score early it seems that everything falls into place. It makes the opponent change their strategy and often lose their way."