Tom Pope's 80th minute penalty the difference as Mark McGhee's first game in charge ends in defeat
Port Vale had a great chance to go ahead 11 minutes in when David Worrall found Tom Pope in a shooting position, but Jamie Stephens produced a fine save to keep his effort out.
Vale had another excellent opportunity in the 57th minute when Pope's shot conviently fell at striker partner Anton Forrester feet, only for his effort to be denied by and unbelievable close range save by Stephens.
The Bees could have take the lead moments before the decisive penalty. Jack Taylor lofted a ball over the top of the Vale defence and Simeon Akinola raced onto the end of it but his effort was comfotable for Ryan Boot.
It was a game of very few clear cut chances for either side and the breakthrough eventually came when Pope, League Two Player of the Month, fired home a spot kick straight down the middle for his ninth goal of the season.
Referee Anthony Blackhouse was initially hesitant to point to the spot in the 79th minute when James Gibbons was brought down by Simeon Akinola, but after a word from his linesman, gave the decision.
Barnet now travel to Newport County on Tuesday night as they continue to go in search of their first win since mid-September.