Japan's Ryota Murata said Sunday he has never felt so beaten up following his loss to Rob Brant of the United States in the WBA middleweight world title bout the previous day.

The 32-year-old Murata, the 2012 London Olympic middleweight champion, said he was only able to sleep for 30 minutes after the one-sided match that saw him on the back foot for most of the 12 rounds against his speedy opponent.

"I'm really bad against boxers who are quick on their feet. I took a lot of blows," Murata told reporters in Las Vegas. "It's the first time I've taken such a beating."

In the second defense of his world title, Murata lost to the mandatory challenger in a unanimous decision at the Park Theater. Brant, fighting in his first world title match, dominated from the outset, throwing 500 more punches than Murata.

Murata, who fell to 14-2 with 11 knockouts, was asked if he intended to continue boxing or retire.

"I can't answer that yet. I want to talk about it with the people around me," he said.

"I don't have any regrets because I have confidence in what I've done up to this point. Hopefully, when I look back at this in 10 years -- or maybe even in one year -- I'll be glad I experienced a fight like this."

While Murata admits it was a one-sided loss, Akihiko Honda, the head of his Teiken gym, said it was not all the boxer's fault. In September, Murata's preparations were slowed when he came down with a fever.

"We were all off guard. It was true he was not in the best condition," Honda said.