Zhilei Zhang respected Joe Joyce prior to their fight Saturday night because Joyce took a risk when he could’ve protected his status as the mandatory challenger for the WBO’s heavyweight title against a lesser opponent.

China’s Zhilei has an even higher opinion of London’s Joyce now that they’ve fought. Joyce took a lot of flush punches for five-plus rounds and kept coming forward until referee Howard Foster decided the severe swelling around his right eye was too much damage to allow Joyce to continue.

Foster waved an end to their scheduled 12-round bout at 1:23 of the sixth round at Copper Box Arena in London.

“I still respect him,” Zhilei told IFL TV through a translator following his impressive victory. “Actually, I respect him more after the fight. I feel like he’s a great fighter, very tough. He gave me a lotta pressure, but I made it through.”

Joyce (15-1, 14 KOs) has a clause in his contract that entitles him to an immediate rematch with Zhilei. The 37-year-old Joyce indicated after suffering his first professional defeat, however, that he might take an interim bout before he goes forward with a second fight against Zhilei (25-1-1, 20 KOs).

“Let’s see what Joe Joyce wants to do,” Zhilei said. “If he wants a rematch, I’m here.”

The 39-year-old Zhilei has plenty of options if Joyce decides that he wants to face another opponent next.

By winning the WBO interim championship from Joyce, he also took Joyce’s spot as that sanctioning organization’s mandatory challenger for Oleksandr Usyk’s WBO belt. Ukraine’s Usyk (20-0, 13 KOs) has two other mandatory defenses due, against Daniel Dubois (WBA) and Filip Hrgovic (IBF), before he would be obligated to fight Zhilei.

The 6-foot-6, 278-pound Zhilei is now promoted by Frank Warren’s Queensberry Promotions, which also represents WBC champ Tyson Fury and Joyce. Fury (33-0-1, 24 KOs) needs an opponent for a return to the ring this summer and Zhilei at least became a viable option for Fury’s next bout by beating Joyce.

The 6-foot-6, 256-pound Joyce entered the ring as a 9-1 favorite to be Zhilei, who dropped and tested Croatia’s Hrgovic (15-0, 12 KOs) in his previous appearance. Zhilei lost that 12-round bout by unanimous decision August 20 in Jeddah, Saudi Arabia, but he demonstrated early in his fight with Joyce why he was such a risky opponent.

Zhilei landed numerous left hands versus Joyce and wobbled him during the second round. Joyce said he could still see out of his right eye when their fight was stopped, but he didn’t complain about the outcome.

“Since I hit him with the first couple shots in the first round, I know he [couldn’t] make it,” Zhilei said. “I know that. And this is why I’m in London. [I knew] I’m gonna take it away from him.”

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