Naoya Inoue rose from the canvas to take out Ramon Cardenas and defend the undisputed super-bantamweight world championship.

The brilliant Naoya Inoue is a pound-for-pound superstar and a two-weight undisputed champion.

But Cardenas, inspired in his performance at the T-Mobile Arena in Las Vegas on Cinco De Mayo weekend, came with an upset in mind.

The challenger swallowed a hard straight one-two combination at the end of the first round but made a stunning breakthrough at the end of the second.

As Inoue was letting his heavy hands go, he wandered square on. Cardenas bobbed his body down and drove back up to blast a left hook flush into the champion’s chin.

It dropped Inoue heavily.

In the next round Inoue had to regroup. Cardenas, though, kept the heavy strikes coming. Inoue just ducked beneath a big right hook but a left hook from his opponent saw him stumble back a couple of paces.

Cardenas landed a solid right cross in the fourth round, but Inoue began to turn the flow of the contest his way.

A savage wide left hook from Inoue smacked in. The champion ripped an uppercut in, too, and his right began to rock Cardenas. He opened up with abandon, but Inoue had now established his timing and was landing with real power.

Adapting to his opponent, Inoue took command. In the sixth round he smashed Cardenas across the ring. Backing the challenger into the ropes, Inoue opened up on him.

Cardenas tried to smile. Baring his mouthpiece in an effort to pretend he wasn’t hurt, Cardenas was in trouble.

Eventually Cardenas hauled himself off the ropes and sent a fast left hook streaking down at Inoue. But the Japanese star resumed his assault, hammering punch after punch into Cardenas, leaving the American now, with little else left, to show off his toughness.

But Cardenas couldn’t withstand much more. In the seventh round he felt a body shot and wilted just for a moment.

A left to the body sent Cardenas staggering back. Inoue opened up with a blazing combination of headshots. The right hit in, the left hook followed and then a triple right saw Cardenas fall into the corner post.

There was no escape for Cardenas. At the start of the eighth round Inoue subjected him to an unrelenting storm of punches and the referee had to intervene to spare the challenger.

The unified WBO, WBA, WBC and IBF world titles remain in Inoue’s possession.

But Cardenas had put in a fine effort. “I never cared about losses. It’s about the best fighting the best,” Cardenas said. “I dreamed about fighting in front of thousands of people in Las Vegas. So I came to give everything.

“I told my trainer, that if I’m going out, then I’m going to go out on my shield. That’s what I did.”

Inoue acknowledged how exciting the bout had been. “By watching tonight’s fight, everyone is well aware that I like to brawl,” the champion said afterwards with some understatement.

“I was very surprised [at the knockdown], but I took things calmly and put myself together.

“It got loose in the second round. From then on, I made sure to not take that punch again.

“I knew he was tough,” Inoue added. “Boxing is not that easy.”

On the undercard Rafael Espinoza overwhelmed Edward Vazquez to defend the WBO featherweight world title. He had Vazquez going in the fourth round and put him under further pressure in the fifth, before eventually stopping him in seven.

“The people deserve these types of fights. And, as a Mexican fighting on this important Mexican date, I did it with all of my heart, and I will continue doing so,” Espinoza said.

“In order for a new Mexican idol to be born, I’ll need to fight against the best. So, I’m here. I’m the champion. And I’m here to fight against the best.”

Emiliano Vargas, the son of Fernando Vargas, scored another eye-catching knockout when he floored Juan Leon in the second round, maintaining his unbeaten record.