"It's going to be difficult for me, it's lucky it's a friendly match! And let's make sure it is one," the pontiff said in a meeting with stars Lionel Messi and Mario Balotelli and their team mates.
Francis, a lifelong fan of Argentine club San Lorenzo, called on the teams to make sure they used their popularity to give a good example to their fans.
"You, dear players, are very popular. People follow your example, off the pitch as well as on. You have a social responsibility," he said.
He also stressed the importance of "beauty, camaraderie and altruism" when playing football.
"Otherwise something is missing from the match, even if you win. There is no place for individualism, everything should be about the team."
The pope also warned the teams about steering clear of the violence and money often attached to the game.
"Football has become a business. Take care that it does not lose its sporting nature," he said, calling for an end a culture of competitiveness which inspires hooligans to violence and drives families away from stadiums.
The players presented Francis with a personalised shirt from each team with his name on it, as well as a silver vase from the Argentinians and an olive tree from the Italians.
"Please pray for me, so that I too, on the 'pitch' God has placed me on, can play an honest and courageous game for the good of everyone," the pope said at the end of the meeting.
Italian goalkeeper Gianluigi Buffon described it as "a day which will remain in our hearts for ever".
The two sides meet at Rome's Stadio Olimpico tomorrow night. The game kicks-off at 8.45pm.