Andy Ruiz Jr. has said that Anthony Joshua is "not good at boxing" with the two fighters set to meet in a rematch before the end of the year.
The Mexican produced one of the greatest upsets of all time when he knocked out Joshua in the seventh round at Maddison Square Garden to claim the WBA, WBO and IBF world titles.
A rematch is scheduled for Nov/Dec and Ruiz is confident that he can claim another victory over the former champion.
"I know his flaws," he told a news conference. "I can do a lot better. The only thing that he can do is just run around, he's not good at boxing.
"The rematch is going to be the same. I am going to be more prepared and more ready. People thought I wasn't going to do anything, I was too big, too overweight.
"There is going to be a lot of changing, I am going to come at a better weight this time. It's going to be a hell of a fight."
Joshua was knocked down four times during the fight and he sent out a video message to his fans explaining his reasons for the defeat.
Joshua's promoter Eddie Hearn confirmed that the rematch has been triggered with a venue for the fight to be confirmed soon.