Mexico take on Cameroon in Group A's second fixture, after hosts Brazil kicked off the tournament with a 3-1 win over Croatia on Thursday.
And defender Marquez is relishing the opportunity to face off against former club-mate Eto'o, alongside whom he played from 2004 to 2009.
"It's going to be something special, as he is a good friend of mine, and we spent a good time being team-mates in Barcelona," he said. "But now he is my opponent and I'll have to do my job and particularly it will be almost always on him.
"So I'll try my best, knowing that he is an important player for Cameroon and he is one of the pillars of this team, so I´ll try to do my best."
Mexico have made it to the last 16 of the last five World Cup tournaments, and Marquez made an impassioned vow to the country's supporters.
He added: "Luckily I have the experience of being in a World Cup before, and heard stories of people from Mexico that make a great sacrifice to come to support us.
"We know about that heavy responsibility, of that effort all the Mexican people make, and yes, we feel that responsibility to give our best, to make an effort to give them the joy that all these people come looking for and I think that the effort, sacrifice, running the whole game, trying, fighting for this colours it's what we have to give back to the people.
"If that give us good results, even better, we wish. I think the attitude and momentum that we can show to give that joy to all of them, I think that will also be important."
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