Claressa Shields is widely tabbed as the 'boxer' in her upcoming clash with Savannah Marshall, who knocked out 10 of her 12 opponents.

Shields and Marshall will battle for the WBC, WBO, IBF, WBA middleweight titles on September 10 at the O2 Arena in London.

On the other hand, Shields has only knocked out two of her 12 opponents.

Despite the knockout records, Shields is not concerned with Marshall's punching power. 

"You have to look at the opposition. I accept her knockouts but I don't respect them because of the opponents that they came against. In my 12 fights I fought against girls who were undefeated, girls who were champions," Shields told Sky Sports.

"I went in there against girls who I wasn't supposed to beat early in my career and I destroyed them whether it was a knockout or not."

Shields believes Marshall is underestimating her. 

Marshall defeated Shields, by decision, when the two boxers were amateurs. That was the only defeat that Shields ever suffered as a pro or amateur.

"Her first weakness is underestimating me," Shields said. "That's the first and I think her mindset has stayed in 2012 at the World Championships in China [when Marshall beat her in the amateurs]. For all these years she hasn't been able to move forward from there. She also has been declining as far as her skill.

"I know I'm going to go in there and look phenomenal and I know I'm going to go in there and land the big shots and be in control of the fight like I always do."

Shields could easily see the scenario of the upcoming grudge fight ending by knockout, but she predicts Marshall will be the one to get knocked out. 

"I think now my knockout journey starts and I'll be knocking out girls from here on out," Shields said.