World champion Mikaela Mayer outpointed Briton Sandy Ryan for the second time to defend her WBO welterweight title in Las Vegas.

American Mayer, 34, was the deserved winner in an entertaining rematch between the two bitter rivals.

After some close early rounds, she dominated the middle of the fight with her higher punch output, shot selection and body work.

Ryan, 31, came back strong towards the end, landing some hurtful punches as blood streamed down Mayer’s face following a clash of heads at the Fontainebleau.

But with scores of 97-93, 97-93 and 98-92, the Californian won by a unanimous decision over 10 rounds.

“I thought it was close. I thought I was doing well into the start and then I got into a fight,” she said.

Mayer dethroned Ryan on points in September, a result which was marred by the Englishwoman being hit by a can of red paint before leaving for the venue in New York.

“The women are getting better and better – me and Sandy just set the new bar on what competitive fights should look like,” said Mayer, who extends her record to 21 wins from 23 bouts.

She called for an undisputed fight against Welshwoman Lauren Price, who holds the three other welterweight world titles, next.