Port Vale fans shouted for manager Dean Glover to be sacked after in-form Lincoln extended their unbeaten run to seven games with a 1-0 victory.
The visitors took charge from the first kick and star man Dany N'Guessan had already forced a smart save from Joe Anyon before he opened the scoring in the 13th minute.
A left-wing corner from Scott Kerr came back off the far post and took a couple of deflections before N'Guessan fired in the loose ball from five yards.
Vale attempted to find a way back as Kyle Perry's header was tipped over by Robert Burch after Paul Edwards had delivered an inviting cross.
The home side, booed off at half-time, attempted to rally after the break as James Lawrie and Louis Dodds both had decent efforts on goal.
But Lincoln thought they had scored a second goal on the hour when a header by Lenell John-Lewis was ruled out for pushing. And Vale did not threaten the visitors goal until the closing stages when Burch twice denied substitute John McCombe.
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