Joe Joyce feels much more confident entering his rematch with Zhilei Zhang than he did when he stepped into the ring for their first fight.

Five months after Zhang upset him by sixth-round technical knockout, Joyce is certain that he is better prepared for their rematch Saturday night because the gigantic British heavyweight was more focused and worked harder in his recently completed training camp in Las Vegas. “The Juggernaut” admitted that he underestimated the huge Chinese southpaw while preparing for their April 15 bout at Copper Box Arena in London.

Zhang’s speed and accuracy troubled Joyce, whose lack of head movement was again an issue for the 6-foot-6, 256-pound former WBO interim champion. Severe swelling surrounding Joyce’s right eye caused referee Howard Foster to stop their fight on the advice of a British Boxing Board of Control doctor.

The loss cost Joyce (15-1, 14 KOs) his interim title and his spot as one of Oleksandr Usyk’s mandatory challengers.

“It exposed a lot of mistakes that me and the team made in the camp,” Joyce said during a press conference Thursday in London. “And it’s about like correcting those and, you know, going to the next fights, not overlooking Zhang, but need to get those things right. And it kind of exposed them, and like made me have to deal with them and really focus and get more dedicated on what I’m doing, and just really improving, to come back stronger and grab that title back.”

Queensberry Promotions’ Dev Sahni, who moderated the press conference, asked the 38-year-old Joyce to elaborate on the changes he made during his most recent training camp. The 2016 Olympic silver medalist didn’t provide details, though, on how he worked with trainer Ismael Salas.

“Well, it’s just like small changes,” Joyce said. “You know, a lot of small changes make a big difference, and that’s what we’ve done.”

The 6-foot-6, 278-pound Zhang (25-1-1, 20 KOs), who turned 40 after recording the biggest win of his career, is a slight favorite to beat Joyce in their 12-round rematch. Joyce was a 9-1 favorite entering their first fight, which was close on the scorecards entering that fateful sixth round.

Joyce led by one point, 48-47, through five rounds on the card of English judge Phil Edwards. Two American judges, Wisconsin’s Mike Fitzgerald and Florida’s Efrain Lebron, had Zhang ahead by the same score, 48-47, entering the sixth round.

Their second clash for Zhang’s WBO belt will headline a TNT Sports telecast in the United Kingdom and Ireland (7 p.m. BST). ESPN+ will stream the Zhang-Joyce rematch as the main event of a doubleheader set to begin at 5 p.m. EDT in the United States.

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