The 11 invited children received custom uniforms from Barcelona players before taking a commemorative photo during the team's evening training session in Yokohama.
Star players such as Lionel Messi and Xavi presented their special guests with Barcelona jerseys, each with their own names printed on the back.
"[Messi] was as cool as I thought he'd be," said 17-year-old Hikari Niizuma, who shook hands with the two-time Ballon d'Or winner.
"I don't think I can wash my hands again."
Barcelona will play Asian champions Al Sadd in the Club World Cup semifinal on Thursday night in Yokohama's Nissan Stadium.
"[Messi] was as cool as I thought he'd be," said 17-year-old Hikari Niizuma, who shook hands with the two-time Ballon d'Or winner.
"I don't think I can wash my hands again."
Barcelona will play Asian champions Al Sadd in the Club World Cup semifinal on Thursday night in Yokohama's Nissan Stadium.
