many years ago I read a fantasy novel in which there was a musical competition. The two contestents played the same tune a total of four times. Each played the tune solo; then they played it together - once with each of them as "lead".

The audience went bonkers for the "other" musician. The panel of judges however awarded the prize to "our hero". He protested, feeling the other musician had performed better. The judges did NOT reverse themselves - the rational being that when judged against their individual performances the "other" musician improved when he played with the hero. And he improved MORE when he played with the hero supporting him. "our hero" on the other hand, did not improve while playing in the duet, and in the judges opinion was the reason for the first players improvement. They therefore considered him to be the better musician.

Makes sense to me.