TOKYO (AFP) - Playmaker Juan Roman Riquelme has been training with Argentine giants Boca Juniors as they target their first Club World Cup despite FIFA barring him from the tournament.

The sport's governing body ruled out Riquelme, who recently transferred from Spain's Villarreal to his old club, because he missed the November 23 deadline to join Boca's preliminary list of players.

But he is in Japan to offer moral support.

"It is a very important tournament. I will stick together with teammates and support them even though I am not allowed to play," the 29-year-old midfielder told Japanese reporters.

Riquelme was seen training with the team on Tuesday for the first time since he arrived on Monday. He also played in a 20-minute mini-game.

"Even if Riquelme doesn't stand on the pitch, his presence is important. He can make us feel calm by just being here," Boca captain and striker Martin Palermo said.

Riquelme played for Boca between 1996 and 2002, helping them win six league and international titles.

He also played on loan from Villarreal during the Argentine side's victory in South America's Libertadores Cup, which won them a ticket to this tournament of continental champions.

Boca take on unfancied Etoile Sahel of Tunisia in the semi-finals here later Wednesday for a possible final on Sunday in Yokohama with Italy's AC Milan.

Milan play Japan's Urawa Reds in Yokohama on Thursday in the other semi-final.

Both Boca and Milan won the Intercontinental Cup three times but have never won the Club World Cup, which was created in 2005 by combining the South America-Europe championship and a one-off world club championship in 2000.