Brazil's players are having a hard time getting used to the World Cup ball.

Although sportswear giant Adidas says the "Teamgeist" (Team Spirit) balls will produce unprecedented performances, the defending champions are not enjoying it so far.

"I still haven't been able to find the best way to strike this ball," defender and free-kick specialist Roberto Carlos said Thursday. "It's very light, the way they are doing it is completely different from before. It seems like it's made of plastic."

Goalkeeper Rogerio Ceni said last week that the ball is very different from what players are used to.

"We'll have to practice a lot to adapt to this ball," Ceni said. "It gains a lot of velocity when it's raining."

Carlos, Ronaldinho and Juninho have been spending extra time during Brazil's training sessions to work on striking the ball.

"We are trying different ways to hit it," Carlos said. "I think the important thing is to hit the goal, we are seeing that the goalkeepers are not being able to hold on to it very easily _ it curves a lot."

Germany goalkeeper Jens Lehmann complained about the ball last month, saying it was made for outfield players and the crowd, not goalkeepers.

With the new ball, Brazil routed Swiss club FC Lucerne 8-0 on Tuesday in a World Cup warm-up. One of the goals was scored by Juninho on a free kick.

Adidas contends that the Teamgeist ball is three times more accurate than its closest competitors, but does not provide data from tests conducted with its robotic leg at a laboratory in Germany.

Adidas has supplied all 32 World Cup teams with 40 balls for training. All 960 soccer balls for use at the World Cup will be inscribed with the date, the names of the teams playing, the venue and the match number.

Each of the 64 games at this year's tournament will have 15 balls to use. Each team and officials will get to keep one ball after the game.

Brazil will play New Zealand on Sunday in Geneva in its final match before heading to Germany to try to win a record sixth World Cup title. It will debut in Group F against Croatia on June 13.