Juan Manuel Marquez stopped Juan Diaz in the ninth round to claim the vacant WBA and WBO lightweight titles on Saturday.

Fighting at 135 pounds for only the second time in his professional career, he looked to be in trouble through the early rounds and was cut above the right eye in the fifth.

However he gradually began to assert himself and opened a cut above Diaz's eye in the eighth with an uppercut before rocking his rival with a left hook.

In the next round a three-punch combination sent Diaz to the canvas and while he beat the count, a stunning right uppercut seconds later ended the fight.

Afterwards Marquez reiterated his desire to go back up in weight and fight Floyd Mayweather Jr.