The Valiants suffered a narrow defeat away at Morecambe after Adam Mayor’s second half strike ensured the Lancashire side secured all three points.
Despite Vale being the better team for the majority of the 90 minutes, it was the home side who grabbed the victory after Mayor powered an effort past Aidan Stone after the interval.
The only goal of the game came after 51 minutes through the Shrimps’ young starlet, who smashed home a low strike at the near post after driving into the box on the left-hand side.
Darrell Clarke made just one change from the side that claimed victory over Exeter City on Saturday, with skipper Tom Conlon returning to the starting 11 in place of Funso Ojo.
Vale started on the front foot and had a good chance to take the lead inside five minutes, but Nathan Smith’s header, from a delightful Sammy Robinson cross, was wide of the mark.
As the half-hour mark approached, Conlon came within inches of breaking the deadlock, but after leaping highest in the area, his header dropped just over the bar.
The hosts' best effort of the first half came through Mayor, who blasted a powerful strike just over the bar from the edge of the area.
Three minutes after the interval, the hero against Exeter, Will Forrester, produced a goal-saving challenge on Michael Mellon when he looked certain to score inside the area.
Vale almost replied to going behind instantly, but Conlon’s curling strike flashed centimetres wide of the righthand post.
The Valiants couldn’t have come closer to an equaliser when Tom Pett saw his spectacular volley cannon back off the crossbar in the 68th minute.
Throughout the second period, Vale pushed hard for an equaliser, and Matty Taylor was the next to come close, but his fine strike was saved well at the near post by Connor Ripley.
Morecambe | Ripley, Love, Gibson, Rawson, Crowley (71’ Taylor), Stockton (34’ Gnahoua), Mellon, Weir (79’ Simeu), Bedeau, Shaw, Mayor
Unused Subs | Smith, Hunter, Cooney, Austerfield
Port Vale | Stone, Donnelly, Smith, Worrall, Garrity, Conlon (63’ Butterworth), Forrester (85’ Proctor), Massey (63’ Harrison), Taylor, Pett, Robinson
Unused Subs | Stevens, Benning, Holden, Agyakwa
Attendance | 4,360 (857 Valiants)