Brazil have come out on top in three previous meetings between the South American rivals at World Cup finals and Luiz Felipe Scolari's side are favourites to win the tournament on home soil.
Chile are plotting to spoil the party when they face the five-time world champions in the first round of 16 clash at Estadio Mineirao.
And Sampaoli has urged his charges to play without fear in a mouth-watering encounter in Belo Horizonte.
He said: "Brazil have a great coach, great players and they're playing at home, but we know we have an opportunity to change history.
"We will face this challenge with courage and conviction, and we will try to fight. Chile will play to win. We can't afford to be fearful."
Chile finished second in Group B behind the Netherlands, who consigned them to their only defeat of the tournament so far.
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