LAS VEGAS — The fight took on a ghoulish tone. It was a living horror show unfolding before 14,726 at the T-Mobile Arena in Las Vegas on Saturday night on Premier Boxing Champions’ inaugural Amazon Prime event.

There was nothing, however, that would wipe away the smile underneath the crusted blood on Sebastian Fundora’s face.

The 6-foot-5½ southpaw fought a brilliantly tactical fight -- a fact that will probably get lost under the gore of the bloodbath that ensued -- in handing Tim Tszyu his first loss, wresting the WBO junior middleweight belt from the Australian and winning the vacant WBC title as well.

Fundora (21-1-1, 13 knockouts) won by split decision, getting the nod on the scorecards of David Sutherland (115-113) and Steve Weisfeld (116-112), which overruled Tim Cheatham’s 116-112 score for Tszyu.

“We've been praying for this moment for a long time and I'm just happy that Tim Tszyu gave me the opportunity and the opportunity became my dream come true,” Fundora said. “I didn't want to break my nose today, but this is my life and this is boxing. I just had to be smart. I used my brain. I hope you saw me use my boxing skills tonight.

“Tszyu is a world champion for a reason. It's an honor to share the ring and make history with him. This means the world to me. My dad is in the running for Trainer of the Year with me and my sister both being world champions. Boxing is our life and I'm very grateful.”

The tenor of the fight changed in the second round.

Tszyu returned to his corner after the round with a gash on the left side of his forehead, which was leaking badly. A replay showed Tszyu was cut when he ducked to avoid a punch and his head caught a piece of Fundora’s left elbow. Fundora ended the round with his nose bleeding profusely.

From there, Tszyu seemed to have troubles. He was catching Fundora’s jab, which Fundora used more effectively than in any previous fight. Tszyu kept wiping blood from his eyes with his gloves as Fundora began tagging him.

The cut did seem to ignite a sense of urgency in Tszyu, perhaps sensing the fight might be a no-contest because of the cut.

As the fourth began, Tszyu’s face was covered in red. He was missing badly, as Fundora kept patiently poking away with the jab.

“I'm a throwback fighter, and whatever circumstances come up, I'll keep going,” Tszyu said. “But all credit belongs to the man who won tonight. These things happen. My momentum was rolling in the first two rounds and then boom, you're blinded completely. This is boxing, it's part of the sport.

“I show up no matter what and always bring the fight. There's no excuses. I'll fight whoever, whenever. If you want a good scrap, you know who to call. It was tough enough fighting with blurry vision and fighting Fundora.”

By the eighth, it was a bloodbath. Fundora had blood streaming down his leg from his nose, and more poured from Tszyu’s forehead.

There were times when referee Harvey Dock began taking a closer look at both fighters. At the start of the seventh, the ringside doctor came up and looked at Tszyu’s cut.

They decided to continue.

Fundora wisely used his jab and stayed away. Tszyu, to his credit, was fighting against both the blood falling in his eyes and Fundora’s jab falling on his face.

Midway through the 11th, punch stats showed Fundora had outlanded Tszyu 165-152. Those numbers increased to 194-175 for the fight.

(Photo by Steve Marcus/Getty Images)

In the last round, Fundora kept a tight defense, which Tszyu split with 1:37 left in the fight with a straight right. It did not affect Fundora, who would soon be living a dream after the scorecards were read.

Sebastian now joins his younger sister Gabriela, the IBF flyweight titleholder, as a rare pair of brother-sister world titlists.

Errol Spence Jr. made his presence known, approaching The Towering Inferno about a possible title shot.

“It's time to get it on,” Spence said. “He's got the big dog now. It's my first time seeing him in person. He's got good height, but we'll break him down. He's learned from his mistakes. He used his distance well tonight.”