LAS VEGAS -- The rivalry between Alexa Grasso and Valentina Shevchenko might need a trilogy.

Grasso and Shevchenko fought to a split draw (48-47, 47-48, 47-47) on Saturday night in the main event of Noche UFC at T-Mobile Arena in Las Vegas. Because of the result, Grasso retained the UFC women's flyweight title.

"Draw -- it's not a loss," Shevchenko said. "But in my case, it's not a victory."

Saturday's bout was an immediate rematch after Grasso beat Shevchenko to win the belt six months ago.

The fight went back and forth. Grasso dropped Shevchenko in the second round. Shevchenko nearly finished Grasso in the third round with a mounted guillotine choke. It ended with Grasso on Shevchenko's back landing punches.

The card was the UFC's first celebration of Mexican Independence Day. The heavily Mexican and Mexican-American crowd booed Shevchenko and the result of the bout. Grasso said she thought she won the fight three rounds to two.

"It was my first main, main event on such an amazing date in Las Vegas," Grasso said. "I always wanted to fight on this date. I'm truly happy with my performance."

Grasso won the first fight via fourth-round submission (rear-naked choke) to take the title at UFC 285 in March. She became the first Mexican-born female fighter to win a UFC championship.

In her postfight interview in the Octagon, Grasso was noncommittal about doing a rematch. At the news conference later on, she said it would be up to the UFC on what's next.

"I wouldn't like to stop the division," Grasso said. "But whatever the UFC says, I'm in."

Shevchenko said she thought she was the rightful winner but that the judges "felt pressure" because it was Mexican Independence Day.

"I was expecting a battle," Shevchenko said. "I fought until the end, and I think I did enough."

Shevchenko said she broke her thumb in the first round and that she didn't want to commit to a rematch until she is fully healed from the injury.

"I don't want to perform at 50 percent," Shevchenko said. "I want it 100. Right now, I don't know what is going to be next, who is going to be next. But I am here. This performance tonight, I showed that I have much more forward to go."

Judge Mike Bell had Grasso winning the fifth round 10-8, which led to the draw. He had Shevchenko winning the first, third and fourth rounds and Grasso winning the second and fifth. Judge Junichiro Kamijo had Grasso winning, with victories in the second, fourth and fifth rounds. Judge Sal D'Amato had Shevchenko winning, with victories in the first, third and fourth rounds.

"I fought with all my heart, with all my soul," Shevchenko said. "The other side, it's my frustration. I think three rounds I won. Two rounds maybe was her. I feel the 10-8 in the fifth round was completely unfair."

Grasso outlanded Shevchenko 64-57 in significant strikes and 219-158 in total strikes, according to ESPN Stats & Information data. Shevchenko landed four of six takedown attempts and had 8 minutes, 37 seconds of control time.

Coming in, ESPN had Shevchenko ranked No. 2 and Grasso at No. 3 in its women's pound-for-pound rankings.

Grasso (16-3-1) is unbeaten in six straight fights, all since moving up to flyweight from strawweight. The 30-year-old Guadalajara native has an 8-3-1 record in the UFC. She was the first UFC champion to have trained primarily in Mexico, doing her camps in her hometown at Lobo Gym, led by her coach and uncle Francisco "Pancho" Grasso.

Shevchenko (23-4-1) had a nine-fight winning streak snapped by Grasso in their previous match. The Kyrgyzstan native, who spent many years living and training in Peru, did most of her training camp in Thailand. Shevchenko, 35, had seven successful title defenses as women's flyweight champion, the most consecutive title defenses by any woman in UFC history as well as the most in one division by any woman. "Bullet" has the most title wins in UFC women's flyweight history at eight.