Listen to Opus No.1 online. Opus No.1 is an English language song and is sung by Tommy Dorsey. Opus No.1, from the album 100 Swing Classics & Big Band Jazz: The Very Best from the Age of Swing, Wartime 1940s and Fabulous 50s, was released in the year 2017. The duration of the song is 2:57. Download English songs online from JioSaavn.