I give it to Bam Bam. Maidana's weakness is when u meat him on the inside (assuming u have either the speed or power to make him cover up). His punches r always wide and looping, and he catches u when u try to get away from him, which gives him room to land his shots. That's why he always hits his opponents behind the head whenever they're on the inside, he doesn't know how to shorten them up and generate power at the same time.
Bam Bam would massacre him on the inside, and I can't think of any reason he'd have to back up, and inadvertently give Maidana room to swing