Its simple math guys just look at it like this:
Kimbo>Ray Mercer>Tim Sylvia>Andrei Arlovski>Pe de Pano>Frank Mir>Brock Lesnar
Kimbo>Tank Abbott>James Thompson>Hidehiko Yoshida>Maurice Smith>Mark Coleman>Shogun Rua who kinda sorta beat Lyoto Machida
Kimbo>Tank Abbott>James Thompson>Hidehiko Yoshida>Mark Hunt>Wanderlei Silva>Dan Henderson>Ryo Chonan>Anderson Silva
Kimbo>Houston Alexander>Alessio Sakara>Thales Leites>Pete Sell>Phil Baroni>Dave Menne>Dennis Hallman>Matt Hughes>Georges St Pierre
Kimbo>Houston Alexander>Keith Jardine>Forrest Griffin>Tito Ortiz>Patrick Cote>Ricardo Almeida>Ryo Chonan>Mach Sakurai>Jens Pulver>BJ Penn
there you have it Kimbo is th number one fighter in the world