Complex sentence: The third is a mantra dear to his heart that helped him win his most important match to date was a quote from the great Mike Tyson It's nothing personal, but I'm going to kill this guy.
Split into simpler sentences: The third is a mantra dear to his heart that helped him win his most important match to date. The wuote/mantra comes from the great Mike Tyson It's nothing personal, but I'm going to kill this guy.