WBA ‘super’, WBO and IBF heavyweight world champion Anthony Joshua has claimed Andy Ruiz Jr is a ‘smarter fighter’ than Jarrell Miller as he prepares to defend his title on June 1.

The Brit will now take on Mexico’s Ruiz Jr, after original opponent Miller failed three drugs tests last month.

Miller and Joshua had been expected to fight at Madison Square Garden at the start of June, but Ruiz Jr has now stepped in after Luis Ortiz turned down the bout.

Sceptics have criticised the fight with Ruiz Jr, with many unhappy with the Mexican’s conditioning but Joshua is adamant that he now faces a tougher fight.

He told Sky Sports: “Obviously with Miller he was 300lbs, his punch output was very high as well – so what I tried to do was adapt my training in terms of size and punch output and what I was going to do to someone that comes forward all the time.

“Ruiz doesn’t weigh as much, he is a lot quicker than Miller and I think he uses punch variety and punch selection a lot better than Miller does.

“His punch output is a lot lower but he is more accurate with his punches. I have to be better with my defence, a lot tighter and be smarter against someone like Ruiz.

“Even though he is not as big and doesn’t work as hard to a certain degree, he is a lot smarter.” Ruiz Jr is a huge underdog at odds of 11.00, while he is 23.00 to win via knockout.