Southport thrashed Barrow, who have now conceded 13 goals in two matches.
Matt Flynn's header put Barrow ahead but James Owen was then sent off when he fouled Southport's Shaun Whalley, who missed the subsequent penalty.
But Liam Willis rounded the goalkeeper to make it 1-1, Karl Ledsham's volley put Southport in front, before Chris Almond's low shot extended the lead.
Ledsham prodded in again for 4-1, Andy Owens tapped home a fifth, although an Adam Boyes penalty saw it finish 5-2.
Barrow had been humiliated 8-1 by Mansfield on Saturday and remain 22nd, two points adrift of safety.