Deontay Wilder is back to his destructive best as he prepares for his upcoming clash with Zhilei Zhang.

That’s according to his sparring partner, Agron Smakici, who told talkSPORT the former heavyweight world champion is firing on all cylinders ahead of the June 1 showdown.

Wilder’s legendary power has floored the best, including Tyson Fury, whom he shared a trilogy of fightsCredit: Frank Micelotta/FOX

It is a must-win fight for the American puncher, who lost to Joseph Parker in his last bout and can’t afford to lose again if he hopes to claw his way back into the world title picture.

Wilder, 38, looked like a shadow of his former self against Parker in December where he appeared hesitant to let his big right hand go as he was battered from pillar to post in a one-sided unanimous decision defeat.

In the immediate aftermath of the fight, boxing critics insisted he had ‘lost his killer instinct’ but that’s not true, Smakici insists.

“People are going down, I can tell you that. People are getting hurt,” he told talkSPORT.com about Wilder’s sparring sessions.

“He is aggressive, he is punching hard, that killer is definitely there… When he punches you it is a different type of power.”

Smakici, who has trained with Tyson Fury and Anthony Joshua added the Bronze Bomber’s power hits different.

“It is like a flash. I have done sparring with all of the best heavyweights but this is a different kind of danger.

“You have to be really careful in the sparring, his right hand is so dangerous.

Wilder looked a shell of his former self in defeat to ParkerCredit: Getty

The former champion is now back to his dangerous best and sparring sessions have been brutal ahead of his fight with ZhangCredit: GETTY

Smakici has previously sparred with Joshua and Fury and told talkSPORT about the pain Wilder is causing during campCredit: Instagram: @Agron_Snakici

“The first time I got in there with him I didn’t anticipate how hard he hits. I got caught with two right hands.

“Thank goodness, my hand was up but I’m telling you, you can see nothing but black for a few seconds. I came back but It’s crazy power, like nothing I have ever experienced before.”

Boxing fans will remember Smakici as the sparring partner who cut Fury during his first camp for the Oleksandr Usyk fight.

Fury and Usyk had initially been scheduled to meet on February 17 but their four-belt shootout was pushed back to May 18 after Smakici opened a gash above Fury’s right eye in sparring, which required 11 stitches.

Leaked footage of the incident revealed that an elbow had caused the cut but Smakici insists it was a ‘freak accident’.

Wilder and Zhang, meanwhile, will headline the unprecedented Queensberry vs Matchroom 5vs5 tournament that precedes the main event at the Kingdom Arena in Riyadh, Saudi Arabia.

Bivol was supposed to face Artur Beterbiev in a much-anticipated showdown for all four major sanctioning body belts at light-heavyweight.

However, the all-Russian affair has since been postponed after Beterbiev suffered a ruptured meniscus in training.

Bivol is now set to face Libya’s Malik Zinad instead.