LAS VEGAS » Cain Velasquez waited 13 miserable months for the chance to put the UFC heavyweight belt back around his waist.

When he finally got Junior Dos Santos back in the cage, Cain didn’t waste another minute.

Velasquez reclaimed the UFC heavyweight title Saturday night, thoroughly battering Dos Santos on the way to a lopsided unanimous decision in UFC 155.

Velasquez (11-1) took early control of the rematch of his only career loss, flooring the Brazilian champion with a big right hand midway through the first round. Velasquez spent most of the match stalking and pounding on Dos Santos (15-2), who never fully recovered from the first-round shot that left him swollen and woozy.

“I was so tired, but I had to endure,” Velasquez said. “My coaches and everybody helped me so much. He’s tough, too. … It feels so good to get this. This is my wife’s Christmas present. I promised her I would do this.”

Velasquez won every round on every judge’s scorecard in the UFC’s traditional year-end event in its hometown. The three judges scored the bout for Velasquez 50-45, 50-44 and 50-43. The Associated Press also favored Velasquez 50-44, giving a 10-8 advantage to Velasquez in the first round.

Dos Santos took the UFC belt away from Velasquez in November 2011 in just 64 seconds, earning a first-round stoppage victory with one vicious overhand right in Anaheim, Calif. Velasquez refused to blame a knee injury for his only defeat — but in the rematch, he demonstrated exactly what he can do at full strength.

“I knew that Junior was a tough striker and he was able to end our last fight that way, so I was prepared for him this time,” Velasquez said. “I was able to effectively use my striking and my grappling to control him throughout the fight and get the title back.”

Jim Miller won a narrow unanimous decision over Joe Lauzon in a sensationally bloody fight on the undercard, and rising middleweight Costa Philippou stopped Tim Boetsch in the third rounds. Yushin Okami grappled his way past Alan Belcher and Derek Brunson easily beat veteran Chris Leben.

But 12,423 fans bought a record $3.2 million in tickets at the MGM Grand Garden to see the second meeting in what seems certain to be a memorable heavyweight trilogy — although UFC President Dana White said Velasquez is likely to fight again, probably against Alistair Overeem, while Dos Santos heals.

“I don’t know if you saw (Dos Santos) after the fight, but he looked terrible,” White said. “It’s going to be a while until he starts training again.”

Dos Santos’ loss was his first in the UFC in 10 fights with mixed martial arts’ dominant promotion, and his first defeat anywhere since November 2007. Dos Santos expected the rematch to last longer, but also predicted a second knockout.

Instead, Dos Santos barely avoided getting stopped in the first round, and he headed straight to a hospital after the bout with what White thought was a broken jaw.

“His game was very effective, and tonight he was better than me,” Dos Santos said. “It’s not usual for me to take a punch, but he walks forward all the time. His takedowns, his grappler game is very effective, so congratulations for him.”

Velasquez immediately showed the rematch would bear little resemblance to the first fight, pursuing Dos Santos from the opening bell and quickly backing up the champion. Velasquez then floored Dos Santos with that huge right to the head midway through the round, and Dos Santos had to cover up in the corner while barely surviving an onslaught of strikes and ground-and-pound.

After brusquely swatting aside his stool and choosing to stand in his corner between rounds, Velasquez went to work on the ground in the second, and the former Arizona State wrestler repeatedly got the boxing specialist into bad positions.

Dos Santos struggled to regain his rhythm, and Velasquez managed another takedown early in the third round before repeatedly tagging the champion with shots that left his face discolored and puffy.

At the final bell, Velasquez collapsed on his back at the center of the cage, pointing skyward with both hands. Although Overeem is tops among several heavyweights who would like a title shot, a third bout between Velasquez and Dos Santos can’t be too far away.

“Cain Velasquez, like you said (last year), I’m going to come back and I’m going to take my belt again,” Dos Santos said.

Dos Santos’ win over Velasquez last year in the UFC’s first fight on American network television catapulted the hard-punching Brazilian heavyweight into an international spotlight. Both fighters injured their knees in the month leading up to their first fight, but stayed in the bout because of its importance.

Dos Santos defended his title against Frank Mir earlier this year and got a lucrative sponsorship deal with Nike while emerging as one of the promotion’s most likable stars.

Miller and Lauzon also turned in one of the UFC’s best fights of 2012 in its final show, starting when Miller opened a gaping gash over Lauzon’s right eye early in the first round. Blood gushed out of Lauzon’s face and onto the canvas, yet he blinked it away and survived the round to a standing ovation.

Lauzon bled substantially for the final two rounds, yet traded big shots with Miller and even took down his fellow veteran, although submission holds were nearly impossible due to the blood slickening both fighters’ bodies. Miller narrowly avoided two submission attempts by Lauzon in the final seconds before celebrating his second win in four fights.

“Joe Lauzon is a tough kid,” Miller said. “I knew I was going to have to bring my best effort to put him away and I was never able to. That’s how good he is on the ground. And even in the last minute, look what he was trying to do to win the fight.”

After two dull main-card bouts resulted in wins for Okami and Brunson, Philippou (12-2) and Boetsch entertained the crowd — but Boetsch (16-5) left his first loss in two years with big cuts on his forehead and nose along with an apparently injured hand. Philippou was impressive in his fifth straight victory, winning as a fairly late replacement for Chris Weidman, his training partner.

In the early fights, veteran Jamie Varner (21-7-1) continued his comeback with a split-decision victory over Melvin Guillard (47-13-3), and heavyweight Todd Duffee (9-2) returned to the UFC after an acrimonious 2 1/2-year absence with a nasty first-round knockout victory over Phil De Fries.