Complex sentence: He made his international operatic debut at the Teatro de Bellas Artes, México City in Tosca; followed by performances of the same opera in Dallas, Texas, opposite the great diva, Magda Olivero.
Split into simpler sentences: He made his international operatic debut at the Teatro de Bellas Artes, México City in Tosca. He followed this with performances of the same opera in Dallas, Texas opposite soprano Magda Olivero.