Just when it looked like Dalton Smith had used the wrong strategy against the heavily armed Subriel Matias, staying in the pocket and punching, the British fighter scored a stunning fifth-round knockout to become the WBC junior welterweight champion in a thrilling fight at the Barclays Center in Recent York.

Fighting in Sheffield, UK, Smith (19-0, 14 KO) was drawn into an ill-advised head-to-head fight with Matias after the first round. While Matias welcomed the close combat, Smith persevered and weathered the storm. Just when it seemed Matias was breaking him down, Smith unleashed a pair of right hands in the fifth round that made him a world champion. The first one shook Matias badly, the second one knocked him down tough. Matias fought back and eventually got back to his feet, but was seriously injured when the referee stopped the fight with less than a minute left in the round.

“For the first time in my career, I was the underdog and the first time I faced a monster,” Smith said. “I canceled all the noise. Tonight was my night.”

Smith made his US debut in a fight with Matias, which almost didn’t happen. In November, before the fight, Matias tested positive for a banned substance in the Voluntary Anti-Doping Association test. However, following an investigation in December, the WBC found him not guilty of violating its drug policy. This would ultimately benefit Smith, who pulled off an upset in a fight full of fireworks from the opening bell. Matias (23-3, 22 KO) moved forward and tried to put pressure on Smith with his hefty hands and high punching power. Smith initially tried to stay on the outside and in the box, but was pulled in in Round 3.

The fight seemed to go in Matias’ favor, as he rocked Smith with uppercuts and punch combinations. But Smith refused to leave and responded with combinations. Matias’ bravado prevented him from retreating and finally caught up with him in round 5 when Smith stepped back and fired a tough right hand that caught Matias in the chin. Matias, who had not been knocked out before the fight, swung at Smith and was met with a second right hand that sent him to the canvas. And that was all Smith needed to become world champion.

“He beat Matias at his own game,” said Smith’s promoter Eddie Hearn. “Matias has never been down or injured before, and now Dalton Smith has declared himself the modern superstar of the 140-pound division. The future is unbelievable.”

Matias won the WBC junior welterweight title by majority vote over Alberto Puello in July and has long been considered the terror of the division. But Smith sent a message that he wouldn’t let one of the toughest fighters in the division stop him from achieving his goal in Brooklyn. And now he will welcome all challengers to his world title.

“Take up the challenge,” Smith said. “I’m one of the best, if not the best in the division. I’m ready to mix with everyone.”