Joss Whedon was recently asked who would win in a fight between Black Widow and Buffy Summers. He answered in explicit detail.
"Buffy would go easy at first, but as soon as Natasha popped her with a Widow Sting, she'd start bringing some slayer brawn to the fray. Natasha's fast, but a couple of good connects and she's wobbling, possibly something broken — she whips out her glock and now Buffy's dodging — right where Natasha wants her. Natasha shoots the cable holding the steel barrels and the