On Sunday night at George Washington University's Lisner Auditorium, Washington Concert Opera explored one of the many Donizetti works that are largely ignored today, Maria Padilla. The experience seemed all the more worthwhile given Washington National Opera's current production of another neglected gem, Lucrezia Borgia. There are amazing things in Maria Padilla, including a soprano/mezzo duet that can stand comparison with the one in Bellini's Norma and some exceptional instrumental coloring. The story is no better or worse than hundreds of other operas -- a Spanish king secretly marries a woman who gets a little annoyed to find out late that he's about to marry a French princess. For almost all of its length, the music provides abundant interest, enough to bring the drama alive even without sets or costumes. At least it did so here, with an enthusiastic cast and the fiery conducting of Antony Walker (I wish he had slowed down once in a while, but his driving approach was hard to resist). The cast included Leah Partridge in the title role; Jennifer Rivera as Maria's sister, Ines (a standout performance); Mark S. Doss as Don Pedro; Justin Lavender as Maria's father, Don Ruiz. Chorus and orchestra got through more on enthusiasm than finesse or tonal fullness. All in all, a memorable night with an unjustly forgotten opera.