Who can challenge Ronda Rousey?

LAS VEGAS -- Referee Herb Dean didn't end UFC 170 early. Ronda Rousey did.

Say what you want about Dean’s decision to stop Saturday’s title fight in the first round, awarding Rousey the first knockout of her career. Given the stakes involved, he probably could have given Sara McMann more opportunity to recover, sure.

But don’t ignore reality, either. Liver shots end fights -- in fact, good ones often look more debilitating than strikes to the head. McMann never argued the stoppage forcefully and it’s quite possible she would not have recovered anyway.

The venom directed at Dean’s stoppage was, perhaps, due somewhat to the fight in general. For all the talk about Olympians and judo vs. wrestling and undefeated records, the main event was a 66-second blowout. Complete blowout.

Fans of the still relatively new UFC women’s division might not have known exactly what they expected to see on Saturday, but a first-inning, run-rule situation that lasted about a minute wasn't it.

McMann was supposed to be the greatest challenge yet to Rousey’s career. She went out with a whimper, thanks to a very effective but visually uninspiring body shot. A quick knee to the midsection and that’s it? The mountain is climbed? Weak.

That perspective unfairly diminishes the level of skill and preparation that really went into Rousey’s finish, but unfortunately, it's bound to exist after a fight like that: Yes, Rousey is amazing, but I’d sure like to see her in a real fight.

As much as Rousey has seemingly enjoyed her one-sided career, she admits that just three years in, she’s already forced to search for (and at times, create) challenges for herself.

“I keep trying to top myself,” said Rousey, two days before fighting McMann. “It’s hard to keep creative and say, ‘What can I do that is better than the last thing?’”

The UFC’s bottom line is unlikely to struggle when Rousey headlines, blowout or not. Consumers of combat sports have long shown a willingness to tune into less-competitive fights, as long as marquee names are involved.

Rousey, however, seems like a champion who wishes to be challenged. Currently, only a handful of 135-pound females appear even slightly capable of providing one.

Cat Zingano was supposed to fight Rousey last year, but suffered a serious knee injury in May. UFC president Dana White has said Zingano will fight for the belt when she’s healthy, but no firm date for her return exists.

Interest in a fight between Rousey and Invicta FC featherweight champion Cristiane Justino, aka “Cyborg,” is certain to amplify this year. Justino recently announced her intent to drop to 135 pounds and “retire” Rousey by December.

On Saturday, White, who accused Justino of being on performance-enhancing drugs one week ago, said she would have to drop to bantamweight and fight outside the UFC before ever receiving that opportunity.

The simple question of whether Justino would be licensed to fight at 135 pounds remains an interesting one. In 2012, she and her manager at the time, former UFC champion Tito Ortiz, said cutting to that weight puts her health at risk.

“That’s extremely relevant, it’s an admission by the fighter,” said Francisco Aguilar, chairman of the Nevada State Athletic Commission. “If she made that comment, she had reasons for making it.

“If the UFC wanted that fight in Las Vegas, the commission would review her application and decide whether or not to approve that bout at 135 pounds. This is one of those situations we’d really have to look at.”

For years, White claimed female fights would never happen in the UFC because the divisions lacked depth. It was Rousey, White says, who changed his mind.

In some ways, though, every lopsided Rousey win validates White’s initial concern about depth in the women’s divisions. Hopefully, that challenge she’s been looking for is on its way.