Angela Rayner warned against "entitled men" underestimating Sue Gray as she spoke to Andrew Marr during Labour's annual conference on Tuesday, 24 September.
The deputy prime minister's comments came amid a row about Sir Keir Starmer's chief of staff and her salary being larger than his.
When asked if criticism against Ms Gray comes from "entitled men who've been to a certain kind of school" who are unhappy at her being at the core of power, Ms Rayner responded: "Underestimate her at your peril."