They've been singing together so long, they're like old friends. It matters not who slays whom, who loves whom, who rises in triumph or dies in agony so long as the orchestra plays and the audience cheers. This is the world of repertory opera, a clique of not-quite Pavarotti-stature tenors and superstar divas and the not-quite-La Scala houses where they play.

In a sense, they're like major-league infielders, whipping the ball around for a double play. There's immense respect for a reliable shortstop, for a first baseman you can count on — Tinkers-to-Evers-to-Chance.

At Seattle Opera this season, the music is by Verdi (three operas in a row: Traviata, Trovatore, Falstaff), performed by what amounts to the cast of Friends, singers familiar to the audience, but, equally important, familiar with each other. Antonello Palombi, the barrel-chested tenor, has been Radames to Lisa Daltirus's Aida, and, in Pagliacci, Canio to Gordon Hawkins's Tonio. Hawkins played Count diLuna is Seattle's most recent Trovatore, in 1997. Arthur Woodley was Dr. Bartolo in Figaro, conducted by Dean Williamson, who also led the orchestra for Pagliacci. And so on.

Palombi makes the most of his two duets with the new girl, Malgorzata Walewska, whose only previous role in Seattle was Judith in last season's Bluebeard's Castle.In Trovatore, she's Azucena, the troubled gypsy; she'll be back again next season as Dulcinea in Don Quixote. They're all so good, they could coast right through this production; instead, they give it everything they've got.

Wagner's Rheingold was composed the same year, 1853, as Trovatore, but If you haven't sipped Seattle Opera's Ring-flavored KoolAid there's more vitality to Verdi. The plot of Trovatore , after all, is no nuttier or more gruesome (immolated infant, vengeful gypsy) than the Ring's (dwarfs, giants, magic dragons). What matters is the music, which isn't "about" anything except itself, and is among the finest in all of Verdi.

The audience doesn't have to know stagecraft to appreciate the spectacle of the Anvil Chorus, or mull Manrico's motivation to understand the intensity of Da Quella Pirra (and the opera's show-stopping high C) as he dumps Leonora and gallops off to save his mother. It's the same thrill as watching Ichiro make a diving catch. On opening night, there was an enthusiastic ovation at the curtain for Palombi's vocal acrobatics and for Daltirus's remarkable singing throughout Act IV (when she's dying of a self-inflicted dose of poison, invariably a good tonic for sopranos).

Trovatore's set is a single, hand-me-down, ship-me-over, raked-castle-parapet trucked in from a 2008 production at Minnesota Opera. It doesn't allow for scene changes, just bizarre lighting effects. The no-budget set actually highlights the team-spirit, "Let's Put on a Show!" staging. It's too cramped for the 50-member chorus but feels just right for the duets and trios, where our friends take their turns at bat, sending solid line drives into McCaw Hall's upper deck.

Seattle Opera presents Giuseppe Verdi's Il Trovatore at McCaw Hall, through Jan. 30. Tickets online or by calling 206-389-7676