PATERSON, New Jersey – Zhilei Zhang sensed in the first round April 15 that he was going to beat Joe Joyce.

The strong southpaw noticed by the way Joyce failed to move his head and how he reacted to Zhang’s shots that his punches would damage Joyce during their fight for the London native’s WBO interim heavyweight title. The gigantic Chinese veteran consistently connected with left hands, until there was so much swelling surrounding Joyce’s right eye that referee Howard Foster took the advice of a British Boxing Board of Control physician and stopped their 12-round fight in the sixth round five months ago at Copper Box Arena in London.

“Actually, when my punch landed on him in the first round, I knew something was going to happen,” Zhang told BoxingScene.com through his translator. “You know, everybody was talking about how tough his chin is, but when I hit him in the second round I saw him stumble a little bit. So, I knew I had him.”

The 6-foot-6, 278-pound Zhang was surprised that Joyce wasn’t a harder puncher because the 2016 Olympic silver medalist had knocked out 14 of his first 15 professional opponents. Zhang (25-1-1, 20 KOs), who trains and resides in northern New Jersey, expected the 6-foot-6, 256-pound Joyce to throw more punches and take Zhang’s punches better than he did as well.

“I felt like that was not Joe Joyce in front of me,” said Zhang, who will fight Joyce against Saturday night at OVO Arena Wembley in London. “That was not the Joe Joyce I was expecting. I was expecting more. The punching power, punch resistance, punching volume of Joe Joyce – you know, everybody was saying he was up there. But in front of me, I just didn’t feel that much. I think his previous opponents went into the ring fighting scared. But I’m ‘Big Bang.’ I bang everything!”

Zhang, 40, is minimally favored entering a 12-round rematch that’ll headline a TNT Sports broadcast in the United Kingdom and Ireland (7 p.m. BST) and an ESPN+ stream in the United States (5 p.m. EDT; 2 p.m. PDT).

Joyce (15-1, 14 KOs), who was a 9-1 favorite in their first fight, told BoxingScene.com that he has taken a more serious approach to this training camp than he did prior to their first fight. The 38-year-old contender believes defensive improvements he made while working with his veteran trainer, Ismael Salas, will serve him well in a second fight against Zhang that Joyce needs to win regain his interim championship and his position as one of the mandatory challengers for IBF/IBO/WBA/WBO champ Oleksandr Usyk (21-0, 14 KOs).

“It’s almost mission impossible for him to change his style,” said Zhang, who made it difficult at times for Joyce to catch him with flush punches. “But what he can change is his strategy. What we did in this training camp is focus on different strategies. If you wanna come aggressive, if you wanna do a full 12 rounds, I’m well prepared.”

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