LONDON — What would you give young apprentices of Barcelona for Christmas? They belong to an elite school. They enter the academy at nine years of age, but they wait and they wait while Barça’s first team, full of world champions, plays dream soccer.

And then, with 84,000 at the Camp Nou stadium, the coach Pep Guardiola says “Boys, this is your call. Take your chance.” The Barcelona story is set to run and run. On Tuesday, with the club already assured the top place in its Champions League group, the coach fielded a largely second-string squad, and still Barça beat the Russian champion, Rubin Kazan, 2-0.

Thiago Alcántara, the already vaunted midfield understudy to Xavi, excelled again. Defender Andreu Fontàs overcame nerves to score in his Champions League debut. And then Víctor Vázquez, a reserve to the reserves, came on to curl the ball into the Kazan net.

Seldom do you hear Guardiola single out a player for specific praise, but he made an exception for Vázquez who, at 23, has come through harrowing knee injury to finally share the nectar of a big victory at the Camp Nou.