Jeff Horn's reign as WBO welterweight champion has come to a crashing end at the hands of Terence Crawford, who claimed the belt with an utterly dominant display on Saturday in Las Vegas.

Crawford was a class above from start to finish, totally overwhelming Horn to hand the Australian a comprehensive defeat - his first in 20 professional fights - with a ninth-round technical knockout at the MGM Grand Garden Arena.

Referee Robert Byrd stopped the fight with 27 seconds to go in the ninth, intervening as Horn withstood an absolute battering from Crawford.

Crawford was making his debut at the welterweight limit and now has world titles in three different divisions, putting him in elite company with Manny Pacquiao, Floyd Mayweather and Oscar de la Hoya.

Horn, a former schoolteacher, was found wanting in his first fight outside of Australia or New Zealand.

As soon it began it was apparent there was a major gulf in quality between the pair.

Horn, who had blown out to 70kg by the time he entered the ring, never looked comfortable.

He walked into too way many hits from Crawford, who clinically picked him off and took total control of proceedings.

It quickly became apparent Horn would need a knockout to win but Crawford's defence was superb, starving him of opportunities and using his superior reach to strike from long range.

Crawford went on a rampage in the eighth round, rocking Horn with the last punch just before the bell but had to wait to finish the job.

Referee Byrd asked Horn to "show me something" in the ninth, but he had nothing left to give.

Top Rank's CEO Bob Arum, who promotes Crawford, was beyond impressed with Horn.

“I compare him, and it’s the highest praise that I can give a fighter ... that he reminds me of Sugar Ray Leonard,” Arum said. “And that to me is a great, great compliment because I always thought that Leonard was the best. And this guy is equal if not better than Ray was. The future is unlimited.”