Pacquiao has come out of retirement in search of Barrios' welterweight title — here's what you need to know.

Manny Pacquiao returns to the boxing ring for the first time in four years on Saturday to face Mario Barrios. The 46-year-old Pacquiao is understandably an underdog given his lack of recent time in the ring. WBC welterweight champion Barrios is 16 years younger than his opponent and has fought five more times than him over the last four years.