LENOX, Mass. Things were pretty much back to normal here at the Tanglewood Festival of Contemporary Music, which ended on Tuesday. In performance terms that meant that the student forces at the Tanglewood Music Center were fully committed to the festival, an improvement over the 2007 installment, when many of the players were siphoned off for an opera production. And with as many as eight rehearsals for some works, the playing was magnificent. The Tanglewood Music Center Orchestra’s program on Monday evening was the highlight, even without its planned centerpiece, the Lieberson work. It began with “Ínguesu” (2003), a piece of inspired madness by the idiosyncratic Mexican composer Enrico Chapela, composed to commemorate a 1999 soccer match between Mexico and Brazil. The orchestra’s sections represent the teams (the winds, Mexico; the brasses, Brazil), the fans (strings), the coaches (piano and harp) and the referee (the conductor, naturally), and the action follows the game play by play: at one point the conductor signals a penalty, and a trombonist is ejected.