When people gain social status they produce more hormones which regulates how much effort is spent on defending social status. When a person win in a competition like sport their hormone rises. The interesting part is that for sport fans, their bodies also react just as they have gain status. The body mimic what it perceive as an extension of itself.
This explain a finding that in sport riots it is usually the winning side that "starts" the fight, through a more fair description is that the winning side reacts more extremely when they perceive to be challenged.