Botha beat referee Russell Mora's count, but with 2:05 left Mora stopped the fight with Botha backed into a corner. It was Holyfield's 28th career knockout.
Two judges had Botha ahead 67-66 when the fight was stopped. The other judge had it Holyfield 69-64.
There were only about 2,200 people in the stands at the Thomas & Mack Center, most rooting for Holyfield.
