We got a bit of backstory for Rosario, and he's hungry for revenge despite nothing being Mashiba's fault. He's just angry at the world for being unfair to him.
It was really sweet getting all the words of encouragement. Hopefully Mashiba can get some rest before the big night.
The way Rosario builds himself up is through anger, man's inner monologue is hating on everyone and why he's the only one who suffers, oh how unfair the world is. Mashiba better beat him up and become the world champ!