NBA's Earl Watson -- Basking In USC's Defeat (Video)

PHX Suns coach Earl Watson went to UCLA and is a die-hard Bruins fan ... which is why he LOOOVED watching USC get bounced from the tourney yesterday!!!

Check out the clip ... Watson didn't just tell us the Providence victory was his favorite upset so far ... but he actually SHUT DOWN the interview when our photog admitted he's a Trojan fan.

Pretty funny stuff.