Two late goals sealed a win for 10-man Stevenage and condemned bottom club Southport to a sickening defeat.
Paul Tait put Southport ahead in the 25th minute when he slotted into the bottom corner before Stevenage hit back through Jon Nurse's close-range effort.
The hosts went down to 10 men after 62 minutes when Santos Gaia was dismissed for an awful challenge on Mark Duffy.
Mark Beard's 25-yard thunderbolt secured victory before Mark Birch's own goal completed Southport's misery.
Stevenage: Julian, Batt, Nutter, Gaia, Henry, Nurse, Cole (Hakim 80), McMahon (Oliver 67), Beard, Hughes, Morison.
Subs Not Used: Potter, Fuller, Binns.
Sent Off: Gaia (63).
Goals: Nurse 49, Birch 90 og, Beard 90.
Southport: Terry Smith, Hocking, Dugdale, Birch, Lane (Rowland 58), Powell, Holland (Blakeman 84), Maamria (Boyd 71), Duffy, Tait, Gray.
Subs Not Used: Baker, Newby.
Booked: Lane, Gray, Dugdale, Rowland, Duffy, Powell.
Goals: Tait 25.
Ref: S Beck (Essex).