Former WBO heavyweight champion Joseph Parker has been studying his upcoming opponent, Olympic silver medal winner Joe Joyce.

Their showdown, for the WBO's interim-title, takes place on September 24 in Manchester.

The winner will be in a mandatory position for a crack at unified world champion Oleksandr Usyk.

There is a rematch clause, with a second bout should Parker come out on top.

However, Parker believes the insistence for a rematch clause is a sign of weakness on the part of Joyce and his handlers. Parker does not have a rematch clause on his end of the agreement, because he feels confident in his ability to overcome the bigger man. 

"I know deep down I back myself 100 percent to beat anyone," Parker, told @idboxingnews. "I want to beat Joyce first, twice, I have to beat him in September, have a rematch and beat him again then I'm free to fight anybody.

"He's not even champion so he shouldn't have a rematch clause, but it's one of those things where they weren't going to make the fight happen unless it was in place. I don't need a rematch clause, for the Joshua fight I didn't need a rematch clause because I backed myself and I back myself now. I think it shows a little weakness.

"Because the first time we negotiated with them they didn't care about a rematch clause. I didn't look the best in the first Chisora fight, then after the second one they wanted a rematch clause, it shows weakness and shows there are little doubts that they think they might lose."

Parker was in action back in December, when he dropped and battered Derek Chisora over twelve rounds for a unanimous decision win.