“Countdown to UFC 210” debuts Sunday at 10 p.m. on FOX Sports 1.

The series goes inside the lives and gyms of four athletes preparing for pivotal battles.

Light heavyweight champion Daniel Cormier braces for a rematch against the man he first defeated for his title, power puncher Anthony “Rumble” Johnson.

Plus, former middleweight champion Chris Weidman focuses on victory as he readies to take on dangerous veteran Gegard Mousasi, who looks to turn his win streak into a title shot.