Real lead the champions by six points going into Saturday's crunch game and are unbeaten in all competitions, in contrast to Barca, who have posted their worst points total after 13 games since the 2004-05 season.
The Catalans have drawn three of their last four games and were held to a 1-1 draw by Real Sociedad in their last league match, which coach Luis Enrique called the worst display since he took charge of the team in 2014.
"I'm not focussing on how they played in their last game, it will be a completely different performance. We're playing against the champions and champions always turn up in the big games, but we also have a team of champions," Zidane said.
"This Barcelona side can cause us harm, I'm convinced about that. Every game is a new story, we know how we can beat them, but they don't have any weak points. It's a face off between two great teams."
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Real's strong position in the standings contrasts with Zidane's first trip to Barcelona last season, when his side trailed Luis Enrique's men by 10 points but pulled off a 2-1 win with a gritty defensive display and two late goals.
Zidane said his team would take a different approach on Saturday, although he dismissed the suggestion that Barcelona's position in the table meant they were under any more pressure to take the three points.
"Last year we went there feeling very nervous but it's completely different this time around. I want us to do what we've been doing this season and take the game to them and play well," Zidane said.
"We both need the points from this game, not just Barcelona, It's not any more necessary for them to win. We are top but we want to win. You want to prove yourself in every game and we want to do that in this game too."
Zidane is without record signing Gareth Bale and key midfielder Toni Kroos through injury but Brazilian midfield anchor Casemiro is set to make his first start in over two months since breaking his leg.
(Reporting by Richard Martin, editing by Ed Osmond)
