Floyd Mayweather Photo: AFP

 Undefeated boxer Floyd Mayweather scoffed at claims he is showing signs of aging, saying he's kept his perfect record intact because of his ability to make mid-fight adjustments.

Mayweather won his second-­straight fight over Marcos Maidana, beating the ­Argentine slugger by a unanimous decision Saturday (US time) at the MGM Grand Hotel to retain his World Boxing Council and World Boxing Association 147-pound titles.

"I can't say what aging felt like. I felt like the winner," said Mayweather, who turns 38 in February. "I can make adjustments instantly and that is one of the pluses on my side."

Mayweather is trained by his father Floyd Mayweather Sr but said he ignored his dad's advice and instead decided to play it safe in the final round of the rematch.

Before the 11th round, Mayweather's father told him to stay out of trouble and save energy in the 11th then come out firing in the 12th to make a good impression on the judges.

"My dad was like in the 12th 'I want you to be sharp. Exchange with him and make it look good,'" Mayweather said.

"I decided to do it the other way. I wanted to box in the 11th and move in the 12th.

"I had a brilliant game plan, even in 12th round. If I knew I had the fight in the bag, why would I try to go out there and fight toe-to-toe? I would mess my legacy up."

Mayweather was frustrated often during Saturday's fight by what he labeled dirty tactics by Maidana. He said Maidana bit him on the hand in the eighth round.

Maidana denies the charge, saying that Mayweather intentionally poked him in the eye.

"We clinched and we came together. My hand was under him and he bit my three fingers. My middle finger busted open through the glove when he bit me," said Mayweather. "I think he needs to move over to MMA. It is extremely dirty."

Unlike their first fight four months ago, Mayweather and Maidana did not attend the post-fight news conference together.

Wearing dark sunglasses and sporting a swollen upper lip, Mayweather looked more beat up this time. He said ­Maidana hit him with one of his hardest punches in the third round.

"I've been in the sport 18 years. Boxing is wear and tear on your body. It is another fight, another victory, and time to move on."

This is Mayweather's fourth fight in a six-fight contract with Showtime. He doesn't plan on fighting again until 2015 and says he could even wait until September.

The boxing champ deflected questions about whether he plans to fight Filipino superstar Manny Pacquiao next.

"I never think about Pacquiao. That's not my focus. I could care less what Pacquiao does."