Derrick James has been pleased by the way Anthony Joshua has bought into his program.

James, the veteran trainer out of Dallas, Texas, runs one of the most in-demand gyms in professional boxing today, with an enviable clientele that includes undisputed junior middleweight champion Jermell Charlo, unified welterweight champion Errol Spence Jr., and lightweight contenders Frank Martin and Ryan Garcia.

Joshua, the former heavyweight champion from London, made the decision to link up with James earlier this year ahead of his fight with Jermaine Franklin, whom Joshua defeated by unanimous decision. It was Joshua’s first fight—and win—since suffering two consecutive losses to unified champion Oleksandr Usyk.

The 33-year-old Brit has spoken glowingly of being in the company of James’ rich roster. Previously, James had trained exclusively in his homeland, mostly with longtime coach Robert McCracken.

According to James, his partnership with Joshua so far has been working swimmingly.

“Everybody wants to say they want to be world champ,” James said in a video published on Joshua’s YouTube channel. “But people are not willing to do what it takes to be a world champ. Even in this gym, you’re put through the test because it’s one thing to mean you want to hang out with champs, you want to hang out with other [top] fighters, it’s another thing to be able to endure the workout and endure the work, so it’s a big thing. 

"He’s been pushing himself, he’s asking me, ‘What can I do more, how can I be better, how can I improve my fitness more,’ and that’s really a sign of a great individual and a great champion. Someone who really wants to be better. And it’s working, he’s doing it, in his 100-degree heat.”

Joshua is scheduled to face late replacement Robert Helenius on Aug. 12 at The O2 Arena in London.

Sean Nam is the author of Murder on Federal Street: Tyrone Everett, the Black Mafia, and the Last Golden Age of Philadelphia Boxing.