Weakened to what extent? She was still stronger than everyone there and on her crew, she still pushed Jinbe back and survived multiple attacks, even from Zeus who has high levels of damage output. Even if you want to ignore that, Jinbe still held off Akainu with his bare hands, and he had no reason to hold back either because he was bloodlusted.
She took Zeus' attack 8 hours before she landed on the ship
Remember that she got skinnier as the day went along
Big mom was so weak that she herself says she feels like she's dying. Get it? In her body she felt like she was going to die just by herself without any outside influence of getting attacked or anything
She was stronger than Jinbei but that's why the only thing Jinbei did was push her and not actually damage her. But as it stands BIG MOM WAS DYING according to herself.
So don't go saying this is some monumental feat. Boh Jinbei pushing her and Jinbei blocking her attack are on the contigency that SHE'S DYING as STATED BY HERSELF.
Hell fuckin Chopper even managed to guard against her in this fuckin state