Mauro Vilhete’s 93rd minute header saw Barnet get back to winning ways on a stormy day at The Hive.
The Bees dominated from start to finish but a second-half thunderstorm had a massive impact on play and it looked like ending level.
However, with just 60 seconds of added time remaining Vilhete leapt in the box to head the ball past Danny Hurst and secure the points.
Barnet’s first opportunity of the match came after just two minutes when Curtis Weston drove a shot straight at Hurst.
Keanu Marsh-Brown impressed in the opening stages and with six minutes on the clock he roasted his full-back and pulled the ball across goal where Southport scrambled the ball to safety.
One minute later Ben Jefford picked up the first yellow card of the match for a late challenge on Luisma Villa.
Marsh-Brown continued to torment the Sangrounders’ defence and he was unlucky not to open the scoring with Hurst denying him twice before the break.
Andy Yiadom had the first chance of the second period but he dragged his effort wide before the impressive Hurst was alert to deny Jake Hyde at the near post.
The next 20 minutes saw quite ridiculous scenes as lashing rain and battering winds created tsunami like scenes rendering both sides powerless.
Fast-forward to the final ten minutes of the match and there wasn’t a raindrop insight as the Bees rallied to have one last push at the Southport defence.
Villa went close first curling a free-kick over the crossbar but Southport threatened on the break and Nick Jupp had to be focussed to deny Osayamen Osawe.
Substitute Ahmed Abdulla blazed over in added time but sighs soon turned to smiles as Vilhete headed past Hurst to seal a much needed win.
The winger ran straight to Uli Landvreugd and Dick Schreuder after scoring and he was quickly followed by the rest of the team who showed a togetherness that the Bees will need if they want to kick on and push up the Skrill Premier table.