Fabricio Werdum does the unthinkable once again in upsetting Cain Velasquez

MEXICO CITY – He had a belt, but Fabricio Werdum was kind of a second-class citizen in the pantheon of UFC champions.

He held the interim heavyweight title, and it didn’t carry either the cachet or respect that the regular championship did.

But after a jaw-dropping performance Saturday in the main event of UFC 188, Werdum is second-class no longer.

Werdum wore down Cain Velasquez and submitted him midway through the third round at Mexico City Arena in their battle for the undisputed heavyweight championship, pulling another of the most stunning upsets in mixed martial arts history.

Werdum was supposed to have fought Velasquez last November for the belt, but Velasquez was injured and pulled out of the fight. As a result, Werdum beat Mark Hunt to claim the interim championship at UFC 180.

On Saturday, he got the real deal with an incredibly good performance before 21,036 stunned fans.

Werdum had more left in the tank when Velasquez, known for his exceptional cardiovascular conditioning, was struggling with the Mexico City altitude and left gasping for air.

It was quite a visual contrast at the end of the second round when Werdum beamed as he walked to his corner, while Velasquez staggered toward his.

When the third round began, Velasquez seemed on his last legs and his kicks carried no power. In a last bid to change the momentum of the fight, Velasquez tried to take Werdum down.

He was successful, but paid for it with his belt. As soon as Velasquez shot, Werdum wrapped his arm around the neck and began placing on the guillotine.

He forced the tap that gave him the biggest win of his career. This is the man who defeated the legendary Fedor Emelianenko in 2010 and now has beaten the two men widely considered MMA’s best-ever heavyweights.

“Fedor in 2010, that was an amazing fight, but nobody believed in me,” Werdum said. “This moment today is the best in my life because I’m the UFC heavyweight champion and I’m the best in the world.”

Because of a series of injuries, Velasquez hadn’t fought in 603 days, since a win over Junior dos Santos at UFC 166 in Houston on Oct. 19, 2013. He didn’t seem to be his usual buzzsaw self, and part of that was his difficulty adapting to the altitude.

Werdum spent 40 days in Mexico training at 10,000 feet, while Velasquez only arrived two weeks out and prepared in Mexico City at 7,500.

“Maybe two weeks wasn’t enough,” Velasquez muttered.

Velasquez came out aggressively at the start and was firing — and connecting — with big right hands. But when he got Werdum down, he opted to make the Brazilian stand up rather than go to the ground and grapple with him.

Werdum is a noted jiu-jitsu expert and a two-time world champion. Velasquez’s strength is taking a fighter down and then pounding him into submission, but he didn’t have that option available to him on Saturday.

He said he’d trained to fight on the ground and disputed the contention he avoided it Saturday, even though that’s how it appeared.

“We knew the fight would be fought everywhere and that we’d have to do that,” Velasquez said of fighting on the ground. “We’re not one-[dimensional] any more. It goes to the ground and we fight there.”

Werdum’s jiu-jitsu is what earned him the submission, but it was set up by his striking. His stand-up has improved dramatically in recent years and in his last three fights, he’s out-struck Travis Browne, Mark Hunt and Velasquez, all of whom are top strikers.

He was popping a jab in Velasquez’s face and mixing in his right hand.

All the while, Werdum remained calm and kept not only his composure but his conditioning. Velasquez, on the other hand, was gasping for air with a long way to go in the second.

“There have been guys who have proven me wrong with my ring rust theory, but 99.9 percent of the time, a layoff of two years, you’re going to have ring rust,” UFC president Dana White said. “A layoff and coming into this type of altitude, it’s tough, man. Cain is well known for his cardio. That’s his thing. He still looked good. I mean, they stood toe-to-toe for the first two rounds blasting at each other, then he started chopping at Werdum’s leg.

“Werdum did a good job of conserving his energy, not moving around too much, standing still and ended up out-cardioing the cardio king.”

And as a result, Werdum is the new king of the heavyweight division. He said he knew this day was coming even though he faced doubters at every step along the way.

“I prepared myself for this moment for two years,” he said. “I believed in myself and my team believed in me. I believed and I visualized this moment a lot of times.”

Few others did, however. Velasquez was about a 4-1 favorite, but that mattered little.

On this night, there was no question about the outcome.

“Nothing was wrong, but Fabricio was the better guy tonight,” Velasquez said.

On that latter point, at least, he got no argument.