Manny Pacquiao's return to the ring at the weekend after a four-year hiatus marked the latest example of a boxer well past his prime who could not resist the temptation of the squared circle and a chance to add to his competitive legacy.

The 46-year-old Filipino came out of retirement on Saturday to fight Mario Barrios but fell short as the American escaped with a draw.

Mayweather, now 48, retired four months after beating Pacquiao and returned in 2017 to defeat UFC crossover star Conor McGregor to run his record to 50-0. Davis, meanwhile, is just 30 years old but is the same height as Pacquiao, would have only a negligible reach advantage and is promoted by the same Premier Boxing Champions apparatus.