Athill, 93, was an editor at publisher Andre Deutsch, which published 18 of Naipaul's books.
She closely interacted with Naipaul, 78, over the years when he was often seen by editors as a 'high-maintenance writer'.
During his remarks about no woman writer being equal to him in stature, Naipaul referred to Athill, without mentioning her by name, and said: "My publisher, who was so good as a taster and editor, when she became a writer, lo and behold, it was all this feminine tosh. I don't mean this in any unkind way".
Responding to Naipaul's remarks, Athill told the Evening Standard: "He always tended toward irritability, and it seems he is losing his grip. It is ridiculous. Taking myself out of it, you only have to think of authors like George Eliot, or Jane Austen - you cannot take it seriously".
She added: "The books may be slightly different in nature because of different experiences, but I don't think gender has anything to do with quality. There is some terrible female writing and terrible male writing.
"He has been asked what he genuinely feels and what he feels seems to me to be foolishness".
In 1975, Athill read the manuscript of Naipaul's work of fiction, Guerrillas, which seemed to her to be undeveloped and incoherent.
She told Naipaul, in a gentle way, that it was not up to his best, which prompted an angry Naipaul to withdraw the book from Andre Deutsch.
Athill wrote about Naipaul's angry departure: "It was as though the sun came out. I didn't have to like Vidia any more".
Athill said it was of "no great concern" to her that they no longer speak, adding: "It became tedious because of his depression and bad temper".
"When he decided to leave the firm I was relieved - it made my life much easier".
Naipaul's comments about women writers have attracted much criticism in the literary world.