The Dutch champions welcome the Spanish giants to the Amsterdam Arena in the UEFA Champions League knowing a defeat could see them eliminated from Group F.
Barcelona won the reverse clash 3-1 a fortnight ago and boast a stellar forward line of Lionel Messi, Neymar and Luis Suarez.
However, coach De Boer believes his team should take confidence from a 2-1 victory over the Catalans in Amsterdam in last season's group stages.
"You always have to show respect [to your opponents] but that doesn't mean you need to fear them," he said.
"We showed last year [against Barcelona] that we can play against top teams. I want to see confidence from my team tomorrow.
"The most important thing is that we keep playing as a team and someone is always close to [Lionel] Messi. They shouldn't be afraid to play against Messi, Suarez or Neymar."
For Suarez the match marks a return to a club where he spent three-and-a-half years, scoring 111 goals in 159 games before moving to Liverpool in January 2011.
De Boer added: "I think it will be emotional for Suarez to come back to the Arena to play his first UEFA Champions League match [this season]."
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