Andy Ruiz's father has lashed out at his son following his defeat to Anthony Joshua in Saudi Arabia last weekend.
The British-born of Nigerian descent reclaimed his heavyweight belts six months after initially losing it six months back.
Joshua outscored the Mexican-American pugilist on the scores card after round 12 of their re-match.
And Ruiz Sr. said his son came into the bout with additional weight - more than he had when he emerged champion in June.
"Andy thought he was going to do good in the weight in the fight," Ruiz Sr told Boxing Social.
"I told him a month ago that 'you're not going to do good at the weight. It's going to be too hard, because you're going to be tired, and you're not going to have the movement'.
"He came overweight, that was the problem. It was too much weight for his body. He weighed 282. Plus after he eats, he was almost 290-something.
"There was no way he was going to do something good, so now he's learned his lesson and now he's going to come back.
"All the fights that he's done in his career, he was 255, 257, 246. The last time he fought, he was at 268, and he felt comfortable, but I told him, 'You have to lose weight', but at that time, we didn't have enough time to lose weight. That's why he fought at that weight.
"He was not listening because of the fame. He was with a Rolls Royce, he was with his friends, he was throwing parties, and not listening to the camp.
"He was running by himself. We were in a house in Manhattan Beach, that we he could come with us, and stay in the house.
"He didn't want to stay with us. He wanted to stay with his friend and try to run by himself. It was the worst camp that he could be doing.
"I don't think nothing about AJ. He's a good boxer and a great person. We love AJ, and he deserved this night to win. But Andy, he didn't do the right things, that's what happened."
YEN.com.gh earlier reported that heavyweight champion Anthony Joshua has shown his little daughter to the world after winning his match in Saudi Arabia.
In a video making waves on social media, the reigning holder of four title belts was seen showing off his daughter after beating Andy Ruiz Jnr.
Joshua was captured carrying his daughter on the shoulder while talking about his willingness to continue boxing and meet other boxers.