By Keith Idec

Before breaking into a rendition of the song Manny Pacquiao wrote recently as entrance music for his May 2 fight against Floyd Mayweather Jr., Jimmy Kimmel asked Pacquiao if he is worried because Mayweather has never lost a professional fight.

The 38-year-old Mayweather (47-0, 26 KOs), a five-division champion commonly considered the best boxer in the world, is approximately a 2-1 favorite over Pacquiao. The last time the 36-year-old Pacquiao (57-5-2, 38 KOs) entered the ring as an underdog, he dominated Oscar De La Hoya (39-6, 30 KOs), who chose not to continue after eight one-sided rounds in their December 2008 bout in Las Vegas.

Keith Idec covers boxing for The Record and Herald News, of Woodland Park, N.J., and BoxingScene.com. He can be reached on Twitter @Idecboxing.