Mascherano had a difficult debut in Barca's shock defeat to Hercules on Saturday.
But he said: "Iâ€™m not worried, but I have to be careful not to get carded after 20 minutes because that affects you for the rest of the game.
"I have to adapt, because Iâ€™ve spent a long time in a much more permissive league in terms of physical contact, and sometimes you forget that when challenging for the ball and so I need to put a stop to that.
"But I want to make it clear that it was not an attack on referees here, itâ€™s just that footballâ€™s different here.
"He [Guardiola] wants me to play the ball a lot more, because unlike in English football, defensive midfielders here play their part in taking the ball forward. Heâ€™s always telling me about positioning and making myself available, and where to be when weâ€™re putting pressure on the opposition.
"But it isnâ€™t really all that different to what I have always done. Itâ€™s more or less the same, just that you play a bigger role on constructing moves."