The new IBF, WBA and WBO heavyweight champion caused one of the biggest upsets in heavyweight history on Saturday night at New York’s Madison Square Garden, where he stunned Joshua to stop him in the seventh round.
A rematch clause is likely to be exercised for a date in November or December – when Joshua had already planned to again fight in the event of victory – but where his unsuccessful United States debut had been intended to continue building his profile, it is where he remains undefeated that the rematch is likely to be staged.
Joshua’s previous fight had been at Wembley Stadium but its lack of a roof and the UK winter is likely to rule out a return there. The roof at Cardiff’s Principality Stadium therefore makes a third fight there probable, as is a return to an indoor arena such as London’s O2.
“We didn’t know what was coming next, in November, December, now we do,” said Hearn. “But there’s a lot of pressure on that fight; the rematch is huge.
“For me, it should be the UK, but we’ll sit down as a team and look at everything.
“I know it didn’t go our way but we said we wanted to create a night that people would remember for a long time; unfortunately they’ll remember it for a shock defeat and an incredible night of boxing.
“But that’s OK; revenge will be sweet and I believe he’ll get it.”
Joshua ruled out the prospect of accepting a rebuilding fight before pursuing an immediate rematch, and the 29-year-old said: “Look out for the end of the year, and what’s next.
“I’ll tidy up, brush off the cobwebs and go again. But it’s a minor setback.
“Trust me, where I was at in life, I’ve dealt with more s*** than this, with some real big losses, and bounced back.
“I’m not dwelling on it. You just correct it, you adjust, you sit down, you focus and you go again.”
Ruiz Jr, also 29 and Mexico’s first world heavyweight champion, revealed that he had long seen flaws in Joshua that he believed he could expose.
He accepted Saturday’s fight with little more than a month’s notice, and said: “I’m going to get back in the gym and work even harder; I’m actually more motivated now I’m the champion.
“Before this fight, I always said I wanted to fight Joshua because I knew I could beat him, I knew he opened up too much. My speed and movement was always going to be too much for him.”