LONDON - China's Zhang Zhilei smashed British Joe Joyce with a sixth-round technical knockout here on Saturday to win the WBO heavyweight interim title.

"This fight was easier than I had expected," said Zhang who traveled from his US basecamp to challenge the 37-year-old Joyce with a stunning pro record of 15-win clean sweep. "I have been working so hard and now I get the reward."

Joyce was cheered by an overwhelming crowd at the Copper Box Arena in Queen Elizabeth Olympic Park, but suffered a lot since the first round from 'Big Bang' Zhang's heavy punches.

The 2016 Rio Olympic silver medallist was staggered time to time and his face was covered by blood often. The referee decided to end the match in the sixth round and Zhang replaced Joyce to become the mandatory challenger for unified champion Oleksandr Usyk's WBO title.

"I want to thank my coach, my team and the fans in China as they had to stay up so late to watch my fight," said Zhang.

"This victory is my best birthday present from my team and myself," said Zhang who turns 40 next month.

But Zhang, whose dream is clinching the world title, didn't think that he would rest too long after the huge victory. "I don't want to wast any time," he said. ■