Becoming the first team to qualify for the next World Cup has seen the Selecao's stock rise, prompting the Chelsea star to sound a note of caution.
Willian hopes the Brazil squad remain humble after qualification for the World Cup was heralded by some as a watershed moment.
The Selecao became the first team, other than the hosts, to secure passage to the tournament in Russia next year, thanks to a 3-0 win over Paraguay and Uruguay's 2-1 loss to Peru.
Five-time world champions Brazil triumphed in Japan and Korea in 2002 but bowed out in the quarter-finals at each of the subsequent two editions of the competition.