Bellatrix v Molly - Question (spoilers)?

Did Molly Weasley legitimately outduel Bellatrix?Or was it the result of Bellatrix underestimating her? I'm not really sure... In the series we never get any idea of Molly's abilities and perceive her to just be a housewife. But then again she is aged and experienced and in the Order of the Phoenix, meaning she must be quite skilled magically. What do you think?