Ammon News - Terence Crawford twice knocked down Shawn Porter and became the first fighter to stop him in their Las Vegas world championship collision.

Terence Crawford became the first man to stop Shawn Porter in a major indication of his brilliance on Saturday night in Las Vegas.

Unbeaten Crawford retained his WBO welterweight championship by twice flooring Porter and ending his rival's resistance in the 10th round.

It was a brutal display of Crawford's merit to be known as the best fighter in the world because Porter, a two-time champion, was the toughest and most experienced opponent of his career.

Errol Spence Jr, the IBF and WBC titleholder who has long been Crawford's most desired rival, left his ringside seat and walked out during Porter's demise.

Porter would tellingly admit later Crawford was a more impressive opponent than Spence Jr.

They exchanged stinging right hands in the second round when a brawl broke out that Porter got the better of.

Crawford smiled sadistically under the intense examination of Porter's trademark pressure.

An accidental clash of heads in the third round opened a significant cut above Porter's eye.

Crawford, who switched from orthodox to the southpaw stance, began controlling the pace in the fourth with the accuracy of his left hand.

But another accidental butt of heads left damage to Crawford's eye, a gritty reminder that Porter had no intention of ceding an inch of territory.

By the ninth Crawford's succession of vicious left hands to the body, a shot he threw constantly all night, were leaving a mark.

Crawford stepped it up a gear by throwing a left to the head as Porter bulldozed forwards causing a knock-down in the 10th.

Moments later Porter was sent back to the floor after Crawford cracked him with a right hand.

Porter thumped the canvas in frustration at twice being so dramatically out-foxed. His father and trainer Kenny Porter had climbed onto the ring apron and withdrew his son from the fight.

Crawford has won all 38 of his fights, with 29 knockouts. This was his ninth stoppage in a row.

*SKY