Mayweather scored a knockout in the fourth round when Ortiz apparently misunderstood the referee's instruction and let his guard down while the fight was under way.
After the bout, Oritz's trainer, Danny Garcia, called the decisive punches "illegal," the Los Angeles Times said.
"We'll do everything we can to get a rematch," Garcia vowed.
The fight itself was a messy affair. The bizarre ending was set up when referee Joe Ortiz stopped the action in order to deduct a point from Ortiz for a head butt.
In the end, Mayweather won his 42nd consecutive fight and added the WBC title to his belt collection.