Mikaela Mayer shared a breathless battle with Maiva Hamadouche before the American emerged as the unified world champion with a unanimous decision win in Las Vegas.

Mayer had to display grit, along with sharp skills during a punishing fight, earning victory from the judges with scores of 100-90, 99-91 and 98-92, which were harsh on Hamadouche’s relentless effort.

Hamadouche, who had been champion for five years, landed 233 of 872 punches, while Mayer was more accurate, landing 239 of 594, as she added the IBF super-featherweight belt to her WBO title.

“[I showed] I could bang it out on the inside. That wasn’t really the entire game plan,” said Mayer.

“The game plan was to use my jab, but in the back of my head, I knew she was going to keep it close, keep me on the inside. Even though we trained for that, just being able to do that for 10 straight rounds taught me a lot.

“This is everything I trained for. It really hasn’t even sunk in, but I’m proud of what I did. I’m proud of my team. We’re going to celebrate this one, for sure.”

Top Rank chairman Bob Arum said: “This was a sensational fight, one of the best fights of the year, male or female.

“These two ladies are a credit to the sport, and they left it all in the ring.

“It was a close fight, but I felt Mikaela did more than enough to have her hand raised.”

Mayer will now target Britain’s Terri Harper, the WBC title holder, and WBA champion Hyun Mi Choi.

She said: “I really wanted to show everyone in the division and the naysayers that I didn’t have the power and the grit to stay in there for 10 rounds with Hamadouche, that I am the best in the division.

“I am coming to be undisputed, and I want the big fights. I’m definitely a threat.”