Liam Warman scored the only goal before half time, after the red mist descended on Old Gold captain Greg Walters.
The result leaves Barry top of the table and four points clear of second placed Llanelli Town, while Carmarthen remain in fourth, nine points behind Barry.
With both sides in the upper echelons of the Cymru South table, attack was certainly going to be the recipe for success, and the opening half produced just that.
For large periods of the first half, it was Carmarthen who had the better chances. Thomas Dyson and Liam Thomas having half chances, but they came to nothing, but they were certainly in the ascendancy.
Then the game changed on the half hour mark. Greg Walters fouled Kayne McLaggon, and after the referee awarded the free kick, Walters kicked McLaggon, who was lying in pain on the floor. The referee had no option but to send him off, in what was a bonkers decision from the away captain.
The sending off certainly boosted Barry’s confidence as they pushed themselves up field and took the lead seven minutes before the half time break.
McLaggon laid the ball of to Liam Warman on the edge of the area. His shot took a deflection and looped over a back-pedalling Nicholas Jones, who had no chance of saving it, and Barry were in the lead at the break.
There’s no doubting Barry were looking to turn the screw after the break, and almost doubled their lead. Jordan Cotterill’s effort looked destined to nestle in the net, but Matthew Delaney made a goal line clearance to keep the deficit to one.
Warman then had a chance to convert a Josh Graham cross, but he couldn’t get any connection on it. If he did, the lead would have been doubled.
For large swathes of the second half, however, the game was played in Carmarthen’s half, and a combination of Barry not executing in the final third and Carmarthen not able to get out and counter made for a tough watch at times.
Carmarthen did find themselves further up the field in the final stages of the game, but their efforts came to nothing, and they left Jenner Park defeated.
Barry will face Cwmbran Celtic at Jenner Park next week, while Carmarthen will welcome Taffs Well to Richmond Park.
Image Credit: Louis James