By Keith Idec

Lennox Lewis changed trainers after Oliver McCall knocked him out in September 1994.

The former heavyweight champion thinks Anthony Joshua should do the same thing. Lewis encouraged Joshua to replace trainer Rob McCracken in the wake of the British superstar’s stunning, seventh-round technical-knockout loss to Andy Ruiz Jr. on Saturday night at Madison Square Garden.

“I say you can’t go to university with your third-grade teacher,” Lewis said Monday, according to London’s Daily Mail. “They won’t have the answers you need at that level. You need a professor by then.”

McCracken has trained Joshua since Joshua was an amateur boxer and has drawn praise for his work with the 6-feet-6, 245-pound former champion.

“McCracken is A1, without question,” Lewis said, “but maybe not the fit for the style AJ needs to fight. I switched to Manny Steward, who understood how to leverage all of my physical attributes and skills, and showed me everything I needed to know for success.

“[McCracken] may not be right for the type of style that AJ needs to master. Aside from that, AJ was not prepared for anything Ruiz brought to the table.”

Joshua, 29, tried to brawl with Ruiz after Ruiz knocked him down for the first time in the third round and didn’t respond well to an opponent that pressured him. Trying to slug it out with Ruiz (33-1, 22 KOs) led to Ruiz sending Joshua (22-1, 21 KOs) to the canvas three more times on his way to winning by TKO.

Joshua did not indicate in the immediate aftermath of his first professional defeat that he was even considering parting ways with McCracken, a former middleweight contender who also trained former ex-super middleweight champ Carl Froch.

Lewis, meanwhile, clearly improved after adding the late Steward as his trainer.

Steward trained McCall for their first fight, which led Lewis to replacing Pepe Correa with Steward. Lewis and Steward went on to work together for the remainder of Lewis’ career.

Lewis stopped an emotionally unstable McCall in the fifth round of their rematch in February 1997 and later scored victories over Evander Holyfield, Mike Tyson and Vitali Klitschko. He announced his retirement in February 2004.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.