Mikaela Mayer, who is currently the WBO's mandatory challenger to Katie Taylor's undisputed crown at 135-pounds, believes the Irish star is on the decline.

Last Saturday night in Dublin, Taylor suffered the first defeat of her pro career when she moved up to 140-pounds to challenge the undisputed junior welterweight champion Chantelle Cameron.

Mayer was ringside at 3Arena, watching Cameron retain her titles with scores of 95-95, 96-94 and 96-94.

Taylor is expected to active an immediate rematch clause, which means Mayer will have a longer wait before the sanctioning body mandates a fight with Taylor.

"I do think Katie Taylor is a bit on the decline. It's not a shot at her because she's 36 and has taken on every challenge possible," Mayer told BBC Sport.

"But if you look back a couple of years, she was so quick and so explosive throughout a ten round fight and it looks like she doesn't have that in her now. She needs to train smarter not harder for the rematch."

Jamie Moore, the head trainer for Cameron, believes the unbeaten boxer is now the pound-for-pound best female fighter in the world.

In her prior bout, Cameron turned back Jessica McCaskill, who reigns as the undisputed world champion at the welterweight limit of 147-pounds.

"If Katie Taylor was ranked number one pound-for-pound, which I believe she was, if somebody's just beaten her then surely that makes her the best pound-for-pound," Moore said.

And promoter Eddie Hearn added his own two cents.

"Jessica McCaskill was undisputed at 147-pounds; she came down to challenge Chantelle for undisputed [at junior welterweight]. Katie came up; she's undisputed lightweight," Hearn said. "She's beat two reigning undisputed champions back-to-back. Incredible run," Hearn said.