Barcelona midfielder Rodri isn't "fooled" by Real Madrid's form heading into his first Clásico on Sunday.
Rodri, 30, returned to LaLiga this summer after seven successful years at Manchester City.
In the league, Madrid have already suffered two defeats while Barcelona are perfect.
"I've known them [Madrid players] all for many, many years," Rodri told ESPN.
"I've played in plenty of knockout ties against them and I realise that one of their great strengths is making their opponents think they aren't that good. They don't fool us -- or at least they don't fool me. Real Madrid are always a formidable opponent, whatever form they're in.
"And as for us -- which is what I'm trying to get across to the lads -- we'll need to be at our very best if we're to beat them."
The match has special meaning for Rodri because he could have joined Madrid in the summer.
"I'm really excited and can't wait to experience it for the first time," Rodri said of the Clásico.
"I've watched it loads of times on the telly, as a fan when I was little, and as I've grown up, I've followed both teams. It's always a special match to play in, whether you're on one side or the other, so I'm really happy."
Rodri, who captained Spain to World Cup glory this summer, said Barcelona need to have a cool-headed approach to the game.
"These are different matches," he said of the Clásico.
"They are matches where emotions run high and where you have to try to put those emotions aside. You have to be as level-headed as possible and stay 100% focused, because these are matches where the outcome is decided by the smallest of details."
Rodri has been praised for his performances for Barça.
"I think the main thing I bring to this team is my experience, that leadership role, organising my teammates and instilling a positive mindset in them," he said.
"Perhaps lifting their spirits during difficult times. In terms of footballing ability, it's clear that the standard is very high.
"All the players, especially in midfield, possess that quality. Obviously, I've come here to make a contribution, but I can offer even more in that regard."
Barça do have to bounce back from their first loss of the season, 4-2 Champions League defeat at Paris Saint-Germain in midweek that snapped an 11-game winning run.
If Barcelona win the LaLiga title, it will be a third straight.
"I don't think it's wise to set specific targets for results, because football can take you down one path or another," Rodri said.
"But it's clear that the perception must be that the club, both as an institution and as a team, is better than it was last year. That's why players were brought in. That's why they've adopted this philosophy of climbing the ladder step by step.
"I believe it's during that climb that you gradually reach the level which brings you closer to winning major honours. That's why we don't set ourselves targets like winning LaLiga or the Champions League."
While a win would seem to be a huge step in the title race, Barcelona defender Pau Cubarsí, told ESPN: "It is a very big gap, but LaLiga is a long season.
"It's only just begun, and whether we win or lose, we have to stay focused because, as we know, anything can change at any moment in LaLiga, and we have to maintain our momentum."
Barça midfielder Gavi agreed. "That's quite a few points, but the season is very long and they could catch up with us again in just two or three matches," he told ESPN.
Barcelona forward Anthony Gordon said he was prepared for the challenge.
"I think favourites go out the window in these kind of games. I think it can go, can go either way because there's so much tension, there's so much competition and the level on show, any player can decide the game like this," he told ESPN.
"So no, I don't think we're favourites. I think it's very equal."