The two La Liga giants lock horns at the Santiago Bernabeu on Saturday with Barca leading their bitter rivals by 11 points, although Madrid have a game in hand due to their FIFA Club World Cup-winning campaign last week.
And, with so much at stake this weekend, Messi is expecting another enthralling El Clasico encounter.
"It would be important to win for what it means, it's always a special game," Messi said. "Real Madrid, at their stadium... winning is an important advantage.
"There would still be a lot of league games left, but it would be nice to be able to end the year with a victory and spend a happy Christmas."