Lennox Lewis believes Wladimir Klitschko would beat Anthony Joshua if his trainer Manny Steward was still alive.

Lewis is also convinced the 40-year-old would never have lost to Tyson Fury with Steward in his corner, and that Klitschko’s biggest challenge in preparing for his April 29 fight with Joshua comes in shifting his focus from Fury.

Steward was widely considered the greatest trainer in boxing history at the point of his death, from complications following surgery for the stomach condition diverticulosis, at the age of 68 in October 2012.

In addition to overseeing the finest years of the careers of greats like Lewis and Tommy Hearns, he is also credited with rebuilding Klitschko’s in 2004 after he was knocked out twice in 13 months.

Steward was influential in the appointment of fellow American Johnathon Banks as his successor as Klitschko’s trainer, but it was under Banks the Ukrainian unexpectedly lost his first fight in 11 years to Fury in 2015.

In April at Wembley Stadium he could be fighting to rescue his career against the highly-promising Joshua, but Lewis’ familiarity with Steward’s abilities have led him to believe the trainer’s presence could have made everything so different.

“If Manny was still here, Klitschko would still be the champion, and he would be a better fighter,” Lewis, 51, told Press Association Sport. “I would have made him the favourite to beat Joshua if Manny Steward was here.

“It’s a big loss, because he needed Emanuel, and it’s really hard to replace Emanuel. In essence he’s training himself, and he can’t train himself because Manny set out a number of different things you could do in different situations. I know them all. I know he has that experience level.

“Who has more experience (out of Klitschko and the 34-year-old Banks)? Who can tell who what to do? It really depends if Klitschko’s listening to Banks. In his last fight when he lost, he wasn’t listening, but Banks was telling him the right things.

“It’s the respect aspect too; if he has respect for that trainer. The fact he’s keeping him around shows me he has respect for him, and he may feel he didn’t listen last time, and may listen this time.”

April’s fight, for Joshua’s IBF title and the WBA title Fury last held, is expected to attract a record post-war British boxing crowd of 90,000.

It will also be Klitschko’s first for 18 months, which means he risks ring-rust against the busier 27-year-old Joshua, but Lewis believes a greater difficulty could be handling his desire to avenge the Fury defeat.

“He’s lost his belts, then he has to wait to fight a guy a whole bunch a months,” said the former world heavyweight champion. “The guy he wants to fight has problems so can’t face him, so he has to wait again.

“Then they put another guy in front of him and say ‘You’ve got to box this guy’. It’s not the guy on his mind, that he wants to beat. Now he has to re-programme his mind to beat this young, strong, good looking guy that punches through walls and can punch a horse and knock him out.

“Now he has to focus on this guy: can he do it? Can he programme his mind that way? This is the question.”