Your answer was Mateo
Correct!
At first, the medals look like they are randomly labelled. But, there is a hierarchy among them.
There’s A, Q, J and K.
J being the “last” among them. In what world would J be seen as the lowest amongst those letters? And the colours black and red be present?
The letters might seem out of sequence but they are in fact mirroring the hierarchy in a suit of cards.
J for Jack, Q for Queen, K for King and the highest, A for Ace.
If Rob came in last as the Jack, then that must mean Mateo came first as he has the A for Ace.
Mateo came first.
The seventh part of the Case Code is: O