The Lionesses went into the game without a win in their last five outings, including a 2-1 defeat to Brazil on Saturday, with Neville insisting he did not feel “vulnerable” about his position.
Chelsea’s Beth England was handed her full senior debut for the friendly against Portugal in Setubal.
The 25-year-old striker had scored for the Lionesses after stepping off the bench in Saturday’s 2-1 defeat to Brazil at the Riverside Stadium.
England created no clear-cut goalscoring chances in another below-par display as the first half ended goalless in Portugal.
But they were much-improved after Neville’s double substitution in the 67th minute, sending on Jodie Taylor and Jordan Nobbs for Beth England and Rachel Daly.
Shortly after, England took the lead in the 71st minute courtesy of a glaring error from Portugal goalkeeper Patricia Morais.
Alex Greenwood’s cross floated too close to the keeper, but as Morais attempted to make the catch, the ball slipped through her grasp and dropped for Mead to convert from close range.
Portugal hit the bar late on but the visitors survived to record their first victory since the Women’s World Cup quarter-final against Norway.
Additional reporting from the Press Association.