Valentina Shevchenko is one of the best women’s MMA fighters in the world. Her older sister Antonina is just getting her start in the UFC, but might not be too far behind.

The Shevchenkos — who have dubbed themselves “The Muay Thai Sisters” — have been training together their entire lives, first in traditional martial arts and now in mixed martial arts. But when they put the gloves on in the training room and go toe-to-toe in sparring, who wins?

Antonina said she has gotten that question plenty. And it’s not really like that. When the Shevchenkos spar, she said, it’s not to win or lose. It’s with a different purpose.

“I’m representing different tasks,” Antonina told MMA Fighting. “I’m not fighting like me, I’m fighting like her opponent fights.”

So for this past training camp, Antonina has sparred with Valentina imitating Joanna Jedrzejczyk, Valentina’s opponent for the vacant UFC women’s flyweight title in the co-main event of UFC 231 on Dec. 8 in Toronto. Antonina, meanwhile, has a fight of her own Friday night — against Ji Yeon Kim at the TUF 28 Finale in Las Vegas. It is Antonina’s UFC debut.

Over the course of the last few months, the Shevchenkos have moved their training camps from Texas to Maine to Las Vegas. It was all part of their strategy. Valentina will be fighting in Toronto, which has similar weather this time of year to Maine, while Antonina will be fighting in Vegas.

“We decided to divide the training camp to spend some time here in Vegas, because I will fight here,” Antonina said. “To train in this climate. And the same to do for Valentina, because she will fight in Toronto. It will be a different climate. It’s a very similar climate. It was late autumn and it was snowing there. Different air, different climate. That’s why we spent time there and here in Vegas.”

That’s nothing new for the Shevchenkos, who were born and raised in Kyrgyzstan; have lived in Russia and Peru; train frequently in Thailand; and shuttle around the United States, from Texas to Denver to Las Vegas and beyond. The sisters and their head coach Pavel Fedotov live a nomadic lifestyle.

“In one location, in one gym, the same for three, four months, it’s a little bit tough,” Antonina said. “You change the location, it’s something interesting. Meet interesting people, different sparring partners, different training. Sometimes it helps you to not get tired too much.”

The siblings are certainly not tired of martial arts. With dozens of Muay Thai championships in their back pockets, they are now set on MMA domination. Valentina is one victory away from becoming UFC women’s flyweight champion. Antonina is in the same division and looking to make her way up the ladder.

The goal for them is to be each holding UFC gold. If Valentina is champion and Antonina is the top contender, they will end up with a decision to make. They will not fight each other.

“Of course, she and me, we will do everything possible for this to happen, this situation where she will be the champion and I will be No. 1 contender,” Antonina said. “She will be defending her title until the time that I will climb up to the No. 1 ranking position. Then we have several choices, because now we have four women’s divisions and different choices to go to. I don’t think about 145, of course, and 115. But 125 and 135. So I think we’ll figure out what to do. But in my case, I definitely have the goal to be UFC champion.”

That journey starts Friday against Kim, a replacement opponent for the injured Ashlee Evans-Smith. Antonina said she altered her training a bit, because Evans-Smith is a wrestler. But the game plan — for Valentina and Antonina — is to be a complete mixed martial artist. Kim is multi-faceted and Antonina said she’ll be ready for that.

“The perfect scenario, of course, is to get an early win,” Antonina said. “To finish the fight as soon as possible.”

Win or lose, Antonina will get on a plane a few days after her UFC debut fight and be in Valentina’s corner at UFC 231, the same way Valentina will be in her corner for the Kim bout.

The two are basically inseparable. And their only dream outside of winning the UFC title is making sure the other does, too. Which is why, Antonina said, there are no victories or defeats in sparring — at least not in the way most people think.

“My goal when I was sparring with [Valentina] was not to win against her in this sparring, but to work like Joanna,” Antonina said. “What would Joanna do in this case?”

She then laughed and added: “Joanna didn’t have any chance in our sparring.”