The former Blaugrana defender believes his side could not consider pulling off a win in the same manner as Celtic achieved against the Liga champions in Scotland last season
The Dutch champions have a tough task ahead of them in their Group H opener against Gerardo Martino's side at Camp Nou.
|2/7||Barcelona are 2/7 with PaddyPower to win Group H.
"It's not nice if everyone thinks Barcelona will win, it means they don't think we're at our best," the ex-Camp Nou defender told reporters.
"The pressure is huge but I am sure we can create problems for Barcelona. We know they're a good team but we will be faithful to our style, that's the important thing. We can't create problems for ourselves.
"I have never thought about playing like Celtic because we don't have the same players. We might be punished for that. We will try to stick to our style because it's what we know best. To follow Celtic's style is too complicated.
"Sometimes we will be under huge pressure and that happens to all clubs who play here. We have to put pressure on Barcelona and stick to our style."
De Boer also highlighted the threat posed by attacking duo Lionel Messi and Neymar going into the clash, although he believes the Brazilian still needs to adapt to the Liga champions' tactical system.
"I have watched all the Barcelona matches, they have tremendous quality," continued the former Barca defender.
"Ninety per cent of the players have been at the club for many years now, except Neymar. Neymar has to adapt to the team and the team to Neymar."
Like De Boer, Bojan Krkic is set to return to face his former club on Wednesday and the striker insists Ajax must not be overawed by the occasion.
"This is the second time I have returned to Camp Nou - I was here last season [with AC Milan]," he explained. "It's a special stadium for me, of course. Barca are the best team in the world and have the best players in the world.
"Our mentality must be to want to win because that's the way we can compete. Our mentality can't be that of losing or seeing it as something impossible. We have to trust our capabilities and do things as best we can."