"Though they didn't get as much "screen time", the supporting roles are at least as important, and these were spectacularly cast. As Sharpless was John Antoniou, sympathetically played to the hilt - you could sense his moral dilemna knowing that Pinkerton had no intention of keeping Cio-cio-san as his only bride." The Flying Inkpot - Concert Review: Singapore Lyric Opera Madame Butterfly (2nd February, 2013)
"The main supporting roles of Suzuki (sung by Anna Koor) and Consul Sharpless (sung by John Antoniou) played critical roles in the success of the opera, with their incredible renditions of "Tutti i fiori" and "Ora a noi" respectively. Koor's soft voice however often did not carry through the theatre, and was occasionally overshadowed by the impressive and powerful baritone voice of Antoniou." The Kent Ridge Common - Review: Singapore Lyric Opera presents Puccini's Madama Butterfly (February, 2013)
"In particular, John Antoniou was outstanding as Nick Shadow, The Rake's evil genius who turns out to be the Devil himself. Saturnine of voice and countenance, he seldom failed to capture the attention." Laurie Strachan "The Australian". 16th February, 1981
"There is no warrant for even the tiniest murmur of dissent from the award of the Sun Aria prize to Sydney baritone John Antoniou. He made good his claim to first place not only with his performances of arias by Giordano and Donizetti, but also possessing a voice of bright, even focus, further and more healthily developed than any other in Sunday night's final. His enunciation and understanding of what he was singing were commendable; his dramatic instinct was unmistakable. This is an award to young achievement not merely to promise." Roger Covell "Sydney Morning Herald". 28th September, 1982