Further reading of McCormack`s biography, gives a different reading of his encounter with Joyce.

From the Biography,
"despite some initial self doubt, McCormack prepared for the Feis Ceol, which included a competition for various types of voices, It was known in advance what pieces must be sung: They were the aria "Tell Fair Irene" by Handel and a ballad "The snowy breasted pearl".

McCormack`s account of his preparation suggests that he worked hard to meet his teacher O`Brien`s expectations, and that his teacher was largely satisfied.

Thirteen Tenors were entered in that division, and McCormack became the 14th after he entered late, aided by the fact that a friend paid the fee of ten shillings, [a large sum in those days] for his entry.

McCormack waited apprehensively through the thirteen performances of each of the two pieces. When his turn came, he asked the pianist who was playing the accompaniments to use a slower tempo and then began.
When he finished, there was sudden and prolonged applause, which was actually forbidden, a rule that had been observed by the audience up to that point.

The Judge Luigi Denza announced, "You have shown by your applause that you have made my decision for me, and you are quite right, The winnner is the young man whom you have just heard".
John`s future wife, Lily Foley, had competed in the Feis the previous year and won the Gold Medal in in the Soprano competition.

It is sometimes reported that James Joyce competed in the same year Feis as McCormack, however he actually sang in the 1904 competition, also as a Tenor, and won the Bronze Medal".

I suppose you can take that as read/