Andy Ruiz regrets that he has not trained hard enough for the title fight with Anthony Joshua. The American lost his four world titles to the British on Saturday.

"I was a bit overweight for this fight and therefore couldn't move as fast as I wanted," Ruiz said at the press conference after the fight in Saudi Arabia. "I thought it would be an advantage that I was heavier than Joshua, but that turned out not to be the case."

Ruiz entered the ring with 128 kilos on Saturday, Joshua weighed 'only' 102 kilos at the 'Clash of the Dunes', as the fight in the open air stadium on the UNESCO heritage in Dirayah was called.

Ruiz held out until the end of the twelfth round, but Joshua was in full control of the fight. The jury was unanimous in choosing Joshua as the winner: 118-110 twice and 119-109 once.

See also: Joshua proud to recapture world titles with '70s-style boxing'

Ruiz apologizes to trainer and father

The Mexican American apologized to his trainer and his father afterwards. "I should have listened better and trained harder. But I had too much self-confidence."

In the run-up to the title fight, Ruiz had already announced that he had enjoyed life in the last six months - after his surprising victory over Joshua in the first meeting. "My life and that of my family have changed completely. I have nothing to lose, because my dream has already come true," said the thirty-year-old boxer.

"I should have taken this fight more seriously," Ruiz realized afterwards. "But I also believe that I can come back stronger. In the future I will again be a heavyweight world champion. Let's make it a trilogy with Joshua."

Joshua already said he was open to a new fight with Ruiz. But it seems much more obvious that the world champion of four boxing federations (WBA, IBF, WBO and IBO) will take on Tyson Fury, Deontay Wilder, Alexander Usyk or Kubrat Pulev first.