Brazil became the first nation to qualify for the World Cup in Russia after they beat Paraguay 3-0 on Tuesday.
Despite having won the tournament five times before, the Selecao's last World Cup ended in humiliation after Brazil - hosts of the 2014 edition - lost their semi-final 7-1 to Germany, who went on to win the competition.
Willian admitted after the victory over Paraguay on Tuesday that the Brazilian players have now recovered from that brutal loss, but insisted the entire squad must be wary about getting carried away following their qualification to next year's World Cup.
"The way we are playing is being watched all over the world," Willian said. "People are saying that the champions are back.
"I think this is really important, to play with confidence. But it is also important to keep humble, realistic, be conscious that we haven't won anything yet. And that our biggest aim is the World Cup.
"I guess we can celebrate for being qualified. We're almost there or we have just sealed our passport, but everybody knows which celebration we want to make the most."
