The first three rounds of the fight belonged to Mayweather (left), who landed punches at will.
Ortiz did land a few, but Mayweather clearly had the upper hand.
In the fourth round, Ortiz had Mayweather on the ropes, in a furious assault from the young boxer.
But during the series of punches thrown, Ortiz proceeded to headbutt Mayweather. Referee Joe Cortez is seen here motioning that Ortiz delivered the headbutt.
Referee Joe Cortez then called time, after which Ortiz and Mayweather touched gloves, indicating that it is fight time once again.
But Ortiz continued to look at the referee, taking his eyes off Mayweather, who promptly knocked Ortiz out with a vicious left and right. It must be noticed in this picture that Ortiz has his hands down, a sign that he was not ready to fight yet.
The knockout did the damage as Ortiz fell to the canvas. Referee Cortex then began the dreaded count.
Ortiz could not recover in time and Mayweather was declared the winner, in rather controversial circumstances.
The world then had a new WBC welterweight champ - Floyd Mayweather Jr.