The ankle caused no pain, but Holyfield took precautions between the ropes to not aggravate it.
"I didn't move as much as I probably could have," he said.
Holyfield trailed on two of the three judges' scorecards but was revving up when he dazed Botha late in the seventh round.
Seeing the foggy South African retreat to the wrong corner, Holyfield honed in as soon as the bell opened the eighth round and sent Botha to the floor with a single right-handed blow. When the "White Buffalo" found his footing, a flurry of punches led to the TKO.
"In the sixth, I started to put a little more pressure on him," Holyfield said. A round later, "I was catching him with clean shots that eventually caused me to take him out."
To Holyfield, the trip had all the trappings of a homecoming, if a poorly attended one. Las Vegas was the setting for many of his crowning achievements, though he had not won there in a decade.
He was a sizable favorite over Botha, no spring chicken himself at 41. Sin City was little enthused, with 3,127 customers interrupting feeding the slot machines to attend.
While the sparse turnout raises questions about Holyfield's marketability, he maintains that matchmakers should consider him against any of the three more legitimate heavyweight title-holders -- brothers Vitali and Wladimir Klitschko of Russia and David Haye of Great Britain.
"My name is still big out there," he said. "The WBF is a legitimate championship."
Manager Ken Sanders seeks to line up a similarly beatable opponent as Botha for Holyfield's next bout in Vienna, Austria, this summer.
"Evander is really popular there," Sanders said Monday. He claimed Austrian officials contacted him with an invitation.
Win there and Sanders foresees a return gig in Las Vegas this autumn.
"Evander is in tip-top form," he said. "I know this sounds crazy, but he looks better than he's ever looked."
Holyfield's financial situation has been downright ugly in recent years, blemished by alleged slacking of child-support payments and the near foreclosure of his manor.
Sanders would not disclose Holyfield's share of the purse, but said it would help the one-time multimillionaire meet some of his obligations.
For several reasons, "I've got to fight more than once a year," Holyfield said. At some point, swollen ankles will take forever to heal.