Javier Mascherano insists Barcelona are not simply "going for a stroll in Japan" when they head to Tokyo for the Club World Cup this month.

The European champions will play their first game of the finals on December 17 in Yokohama, just five days after they host Real Betis in La Liga.

Despite Luis Enrique's side competing to defend their treble of league, Copa del Rey and Champions League titles, Mascherano says victory in the Club World Cup is high on the team's list of priorities.

"Whoever thinks Barcelona are going for a stroll in Japan is totally wrong. We're going with the mentality to play two good games and leave as champions," he told Fox Sports.

"For us, it's a very important tournament because you play it if you win the Champions League. It's the prize that you get for winning that, and that means a lot for us."

Mascherano considers Barca and Copa Libertadores winners River Plate as favourites to reach the final on December 20 but has warned against any complacency creeping in.

"Everything suggests that the two favourites for the final are us and River, but the games have to be played," the Argentina international added.