LAS VEGAS -- There would be no one-punch knockout or highlight-reel head kick here. Amanda Nunes had to really work for this one.

Nunes beat Germaine de Randamie by unanimous decision (49-44, 49-46, 49-45) at UFC 245 on Saturday night here at T-Mobile Arena. De Randamie gave Nunes fits on the feet and did some damage, showing the typically dominant knockout artist Nunes wasn't impervious. But Nunes was able to take de Randamie down time and time again and grinded out a dominant decision victory either way.

"Honestly, I was a little bit off tonight, but I'm the champ, I always have plan A, B, C and more," Nunes said. "If something goes wrong with the first plan, I just go to the next one. I couldn't get my timing well with the striking, so I decided to go to the takedown."

It was the first time Nunes has gone all five rounds since a split-decision win over Valentina Shevchenko at UFC 215 on Sept. 9, 2017.

She now has the most wins among female fighters in UFC history with 12 and is the longest-reigning current champion in the promotion, man or woman, at 1,252 days.

Coming in, ESPN had Nunes ranked No. 1 in the pound-for-pound women's MMA rankings and atop the women's bantamweight rankings. De Randamie was tied for eighth on the pound-for-pound list and No. 2 at bantamweight.

Nunes was already considered the best women's fighter in MMA history. She owns wins over Ronda Rousey, Cris Cyborg, Holly Holm and Miesha Tate. Nunes even beat de Randamie previously, on Nov. 6, 2013. De Randamie was a +325 underdog here.

Nunes mauled de Randamie on the ground in the first round and seemed to expend lot of energy going for a finish with punches, elbows and submission attempts. The champion wasn't the same after that. In the second round, de Randamie caught her with hard combinations and body shots standing up and knees in the clinch.

It forced Nunes to take things to the ground. She is a longtime judo practitioner and Brazilian jiu-jitsu black belt. De Randamie, a striker, isn't nearly as experienced in the grappling arts. Nunes exploited that weakness. She took de Randamie down to start the third, fourth and fifth rounds and barely let her up. When De Randamie did get up, Nunes took her down again. Nunes did land some ground and pound, especially punches to the body, which kept referee Keith Peterson from standing them up due to lack of action.

"My game plan was to go five rounds and work the takedown," Nunes said. "I almost got two submissions, but made some mistakes and I have to fix that. Just a little bit of the technique was off, but I will fix it and next time I will get it."

De Randamie did have a glimmer of hope in the fourth round. She briefly caught Nunes in a triangle choke from her back and managed to get into top position. But Nunes reversed it and took de Randamie down again. The crowd didn't like the strategy, booing the lengthy periods of top control from Nunes and booing Nunes again when the scorecards were read.

"We train everything in the gym, especially the bad positions, so I was OK when she surprised me with the submissions, it wasn't too bad," Nunes said. "Germaine's timing was very good tonight, but she's so heavy with everything she throws, so it was easy for me to time the takedown. This is exactly what we trained for, so I'm happy."

Nunes (19-4) has now won 10 in a row. Her five title defenses in the women's bantamweight division ties her with Joanna Jedrzejczyk for second-most all time in the UFC among women. Rousey, who is retired, is first with six.

Nunes, 31, has not lost in more than five years -- since Sept. 27, 2014. The Brazilian slugger who lives and trains in Florida also holds the UFC women's featherweight title.

De Randamie (9-4) had her five-fight winning streak snapped. The Dutch kickboxer was the first-ever UFC women's featherweight champion after beating Holly Holm in 2017. De Randamie, 35, came in ranked No. 2 by ESPN among MMA women's bantamweight fighters.