Hawk wanted Demetri to tag him in, but Demetri refused because A. he was still angry at Hawk, and B. he was fighting Spanish Hawk, and so, C. he stubbornly needed to beat Spanish Hawk, by himself.
Appropriately, US Hawk ends up fighting Spanish Demetri:
See? US Demetri really did have all this in his head during the fight when he refused to tag in US Hawk:
(also. his name... means "eagle," amazing. Amazing.)
And I do believe that was Spanish Demetri because in the final brawl, this is Spanish Hawk, helping US Hawk:
So I think this is Spanish Demetri, helping US Demetri:
I sincerely hope that Spanish Hawk and Spanish Demetri have a happy future together.