Last night’s UFC 170 provided us with a lot in terms of action – Rory MacDonald and Demien Maia had a war, Daniel Cormier took care of business, and Mike Pyle’s mullet was glorious as always. But the main event, which saw champ Ronda Rousey destroy fellow Olympian Sara McMann in ways that were new and creative for the Queen of All Armbars, was both a boon and a burden for the organization. You see, Rousey is one of their few remaining superstars, but even superstars lose some of their shine when there’s no one to test them – and as of last night, there is no one left on the UFC’s extremely new and extremely shallow female bantamweight roster who could be that suitable challenger.

Which is why both the UFC and Ronda Rousey need Cris Cyborg.

A glance at the UFC roster reveals that there are maybe just two ladies on a legitimate title track – Alexis Davis and Cat Zingano – and no one in their right mind believes for a second that they’d be anything more than fodder for the champ. Rousey would tear their arms off, or TKO them if that opportunity presented itself first. The same fate would await Invicta FC’s bantamweight champ Lauren Murphy. There is only the former Strikeforce champ and current Invicta FC featherweight champ Cyborg.

The Brazilian knows this, and has been taking steps to keep herself relevant. She gave manager Tito Ortiz the boot, who was persona non grata with the UFC, and she swears she’ll cut down to Rousey’s weight class with the help of a doctor. Of course, the rhetoric Dana White spouted off about Cyborg is still somewhat of an obstacle, but he’s been known to eat his words in the past (see: White saying women would never fight in the UFC).

All of which leaves us with this basic fact: There is no one in the UFC left to challenge Rousey, no Olympian with the right credentials on paper and no female fighter who’s sparked any blazes of excitement and speculation in our imagination. There is only Cyborg, the fighter who retired Gina Carano, the fighter whose devastating striking has been the been of nearly all who’ve stood before her.

Can Rousey beat her? For sure, but that’s not what matters. What matters is that for Rousey to be great, she needs great opponents. And Cyborg is the only one left.