LOS ANGELES: Terence Crawford punished Errol Spence on the way to a ninth-round technical knockout to claim the undisputed welterweight world title in Las Vegas on Saturday night. Unbeaten Crawford had knocked down Spence three times and had his previously unbeaten foe staggering under a hail of blows when referee Harvey Dock called a halt at 2:32 in the ninth. Crawford added Spence’s World Boxing Association, World Boxing Council and International Boxing Federation titles to his own World Boxing Organization crown. Crawford became the first undisputed welterweight world champion of boxing’s four-belt era, which began in 2004. A former lightweight and undisputed light welterweight world champion, he became the first man to win all the belts in two weight divisions. “It means everything because of who I took the belts from,” Crawford said. “They tried to blackball me, they kept me out, they kept me out. They talked bad about me, they said I wasn’t good enough, and I just kept my head to the sky and I kept praying to God that I would get the opportunity to show the world who Terence Crawford is,” added Crawford, who improved to 40-0 with 31 knockouts.