...I'm trying to picture the scene you're referring to, but, if I should venture a guess, you're describing the final match between Phi and Aiger.
In that case, scenes like that can be interpreted as a release from a dominating influence (e.g. The wickedness of his Dark Resonance) and
the "clothes" that you see exploding off of Phi are the symbolic and metaphorical depiction of this.
You commonly see anime series with dramatic scenes like this to express this kinda symbolism, so I could say that this scene is the same: a character, at the height of their power or madness, being shed of their wicked or misguided ambition at the moment of their defeat.
The scene following support this: as you can see the effects of this defeat (and dissolution of his Dark Resonance) following the match as you clearly see Phi's madness seemingly vanish and he reverts, more or less, back to his original, more calmer demeanor.