Anthony Joshua has bristled at suggestions that he could be mentally scarred by his shock stoppage defeat to Andy Ruiz Jr in June, telling reporters he has “not become a pussy overnight”.

The 30-year-old, who looked lean and mean in advance of next month’s controversial WBA, IBF and WBO heavyweight title rematch with Ruiz in Saudi Arabia, also denied claims made by the former champion David Haye that his sparring before the first fight with the Mexican-American had been too soft. “We haven’t done anything differently mentally,” said Joshua. “I am a champion. I walked into a boxing gym and three years later I was Olympic champion. I have had one loss but I am not about to become a pussy overnight and not be able to fight.”

As for Haye’s comments, Joshua was almost as forthright. “My sparring has always been technical and he has never been in my camp,” he replied. “I only needed 16 fights to become champion of the world, I have always been a fighter. I have not been protected, Rob has not had me sparring anyone with one arm behind their back.”

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Joshua also laughed off criticisms from Tyson Fury, who said his rival did not look like he wanted to be in the ring against Ruiz before he was stopped on his feet in the sixth round.

“Of course I wanted to be there,” said Joshua. “Tyson is at a different stage in his career, he would never understand what I’m going through. I was ready, I was in a good place.” However, Joshua conceded he would be much better prepared this time having originally expected to meet Jarrell Miller in June before the American failed a drug test and Ruiz stepped in.

Joshua confirmed he had brought in a number of top-quality sparring partners to test him – including the former world title contenders Dereck Chisora and Bryant Jennings – as well as the cruiserweight Andrew Tabiti to try to replicate Ruiz’s style.

“I am doing more shadow boxing in the mirror than I did before. And just more boxing, I did a lot of boxing in my break,” added Joshua, who refused to say whether he planned to enter the ring considerably lighter than in the first fight to neutralise Ruiz’s speed. “I am not really focused on my weight, I am just focused on my sparring. Everyone in the team has different opinions on my weight but I like going off of my sparring.

“I could weigh anything but it just comes down to how I perform in the ring. I am not interested in getting down or up to 110kg and then thinking I am fit. If I am sparring 10 or 15 rounds at 120kg then I am good. The sparring gives me all the information I need.”

His trainer, Rob McCracken, said that Joshua had enjoyed “real good sparring” with partners who had pushed him hard. He added: “Since Josh has been a professional, sparring partners have always come here to try to rip his head off and make a name for themselves. This group of sparring partners has done really well and pushed him every step of the way and we still have three very important spars ahead, where our fight strategy is going to be carried out.”

Amnesty International is among those to have warned that the Saudi authorities are attempting to “sportswash” their human rights record by bringing the fight, billed as the “Clash of the Dunes”‚ to Diriyah on 7 December. However, Joshua and his promoter Eddie Hearn claim they are trying to increase boxing’s global profile.