Whenever a pair of high-level, 125-pound  women compete in the octagon, rest assured the UFC champion is watching.

“Constantly,” Valentina Shevchenko recently told The Post with a laugh regarding if she watches the other flyweight contenders. “I would say when there is a fight between 125ers, I try to watch them all the time because, firstly, it’s interesting to see what’s new in martial arts. Another is you definitely have to know who [are] challengers in your weight class. And the third is I like to watch fights.”

It’s the rest of the world’s turn to watch the No. 1 pound-for-pound woman in the world in action Saturday, when Shevchenko (22-3, 15 finishes) defends her title for the seventh time since capturing it in December 2018. The latest challenger in the pay-per-view co-main event of UFC 275 (10 p.m., ESPN+) from Singapore Indoor Stadium in Kallang, Singapore is Taila Santos, who rides a fought-fight win streak into her first title shot.

Shevchenko has had more time than is custom to scout the competition, as she is coming off the longest layoff — nearly nine months — since she defeated Joanna Jedrzejczyk for the vacant title. Her last fight was a typically dominant TKO of Lauren Murphy in late September, capping her fourth consecutive 2-0 year since dropping down to flyweight when the UFC incorporated the weight class at the start of 2018.

“I wanted to come back sooner, but this date [is] what I was offered,” Shevchenko explains of her elongated gap between bouts. “… I definitely would [have] loved to fight sooner, but this is what happened.”

Even with the late start to her 2022 competition slate, the 34-year-old is committed to finding her way into the cage a second time before the year is up. She’s done it before, having violently knocked out Jessica Eye in June 2019 before cruising to a snoozer of a decision against Liz Carmouche two months later.

Heck, Shevchenko wouldn’t mind sneaking in a third fight.

“I definitely want to fight this year,” said the champion from Kyrgyzstan. “Definitely once, for sure, but if I will be lucky and UFC gives me another spot and a date, it will be twice.”

Not that Shevchenko is getting ahead of herself and the fight with Santos (19-1, 13 finishes), though. Remember: this champion monitors those who may come looking to claim what’s hers.

Studying an opponent only ramps up for Shevchenko when she knows who’s next. That’s when she dives in to learn “strategy, mentality, [and] character” of the upcoming challengers to her throne, in addition to “tactical characteristics.”

“For me, it’s not, ‘Wow, this is [the] opponent in front of me. That’s hard,’ or something like that,” Shevchenko said. “No. For me, it’s analysis and see how to destroy that particular opponent.”

In Santos, Shevchenko assesses a woman who’s a “complete fighter” and possesses a power striking arsenal. Similar to the champion, the Brazilian trained Muay Thai under a parent — Santos’ father coached her, while Shevchenko’s mother is a former champion of the sport.

Shevchenko, too, came from the Muay Thai world before stepping away from competition as she signed with the UFC in 2015. While she enjoys MMA because it is a “complete fight style where you can do anything” such as striking, wrestling and submission grappling, some nostalgia exists for the sport in which she first became a champion.

“What I miss a lot is the spirit of competition,” Shevchenko said. “For example, [at] professional fights in Thailand, there is a stadium and so many fans are cheering for the fighters. They’re making bets, straight there in the gym. And you can see different type [of] people, they are calling to make a bet, and it’s so fun. And the Thai smell, the Thai oil … it’s so charming for me. And this is what I call the spirit of Muay Thai. And definitely, I miss that a lot.”