Sound the upset alarms, Alexa Grasso stunned Valentina Shevchenko with a fourth-round submission win over Bullet to claim the women's flyweight title at UFC 285.

Grasso took early momentum in the fight with her boxing, but it was a rear-naked choke at 4:34 that ultimately forced the tap in the fourth round to claim the belt. In doing so, she became the first Mexican woman to earn a UFC title.

Grasso commanded Shevchenko's attention early in the fight. She came out aggressive, and her boxing led her to early success, giving her a good argument to take the first frame.

Bullet didn't become a dominant champion without the ability to adjust, though. She changed up her strategy and went to a more wrestling-centric game plan in the second round and had success taking Grasso down and maintaining top position.

Shevchenko continued to exploit her advantage on the ground going into the third round. Grasso had brief moments before the fight hit the mat, but Shevchenko was able to control the pace and position.

That control quickly eroded in the fourth round. With Shevchenko once again looking to utilize her grappling, Grasso did the unthinkable. She took the former champion's back and locked in a choke that forced the tap.

Grasso is now the first women's flyweight champion not named Valentina Shevchenko since 2018. The now-former champion's run was the longest and most active in the UFC, with seven title defenses spanning over five years.

Now it will be up to Grasso to try to establish her own run with the belt.

There will be a number of threats who are looking to pry the belt from her. Taila Santos—who battled Shevchenko to a split decision in her last bout—had to withdraw from a recent bout against Erin Blanchfield because of injury, but she is a legitimate contender.

Blanchfield went on to run her UFC record up to 5-0 with a submission win over Jéssica Andrade. She also isn't shy about campaigning for her own shot at the title.

"I'd definitely prefer Shevchenko," Blanchfield said in her post-fight press conference (h/t MMA News). "I definitely think she beats Grasso. I think Grasso is a very tough fighter, but I want to be the one to take the title from her."

Blanchfield didn't get her wish, but her comments could be the basis for a new rivalry in the division.

Then again, most champions who are as dominant as Shevchenko get an immediate rematch. Beating Bullet twice would be a considerable challenge.