Vale stormed into a 2-0 lead through goals from Tom Pope and Jennison Myrie-Williams, with Louis Dodds adding a third to secure the win.
Southend were unable to put pressure on Gillingham and Cheltenham as they were defeated 2-0 away at Burton Albion, and Rotherham beat Accrington 4-1 at the New York Stadium with a brace from Daniel Nardiello.
Bradford lost ground on the leaders, however, as they were beaten 4-2 by Rochdale with Terry Gornell netting a double.
Fleetwood shared a goalless draw with York City at Highbury Stadium, while Chesterfield drew 1-1 with Morecambe at the Proact Stadium.
Exeter were held to a 2-2 draw with Barnet at St James’s Park after defender Andy Iro scored a dramatic stoppage-time equaliser.
Oxford United beat AFC Wimbledon 3-0 away from home with goals from Alfie Potter, Tom Craddock and Sean Rigg, despite striker James Constable being shown the red card.
Wycombe recorded a 1-0 victory over Plymouth at Home Park with Matt McClure netting the game’s only goal early on.