It's so obvious that BM looked superior in that small clash. She overpowered Marco, grabbed him and he wasn't able to do anything at that specific point. Perospero could harm him and Marco looked like he was about to die. But, BM could also just use her physical strength to damage Marco.
Oda just wanted to make Carrot and Wanda look better, so he made them save Marco. That's the only reason.
BM > Marco easily.