Andy Ruiz Jr. has blamed poor lifestyle and weight gain for his heavyweight title defeat on Saturday to Anthony Joshua.
The Mexican was outclassed as the Brit became a two-time WBA, WBO, IBF and IBO heavyweight champion of the world, with Joshua scoring a unanimous 118-110, 118-110, 119-109 points win in Saudi Arabia.
According to Luke Reddy of BBC Sport, Ruiz admitted he failed to reach prime condition before the fight because of excessive partying and celebrating after his shock win over AJ on June 1 in New York. The Mexican tipped the scales 15 pounds heavier before the rematch, and he was dominated by Joshua for most of the fight.
"I should have trained harder. I should have listened to my team and coaches.
"For this fight I was overweight. I didn't move how I wanted to.
"I put on the weight and it was my mistake. No-one knows about the training we had. We did the best we can.
"Being a champion for the first time, being over here and there and missing training, it was hard."
In contrast, Joshua lost weight before Saturday's bout, and his superior mobility was a factor during his victory.
AJ kept Ruiz away from him with the jab, and the Mexican had little to offer during an unimpressive first defence of the heavyweight crown.
"There's no excuses," Ruiz added. "The partying got the best of me. The next fight is going to be a lot different."
Ruiz has quickly asked for a third fight with AJ to gain redemption, and he will want to prove his technical knockout defeat of Joshua wasn't a fluke.
Ariel Helwani of ESPN tweeted Joshua is prepared to fight the Destroyer once again:
The Brit was lethargic and slow when Ruiz handed him his first defeat, but Joshua's preparation was clear for all to see in the Middle East.
Tactically, Joshua was more acute and displayed more purpose, and his control of the fight reinforced his reputation, which suffered damage in the first encounter.
A third fight might not be in the former Olympic gold medalist's best interests, especially as there was a huge gulf between the fighters in the rematch.
AJ appears destined to fight Deontay Wilder or Tyson Fury, and with the heavyweight titles in his possession once again, he has reclaimed his mantle at the top of the mountain.