Southport had a few anxious moments but the outstanding Futcher and man of the match Tim Ryan repelled everything that was thrown at them.
The all important goal came in the 68th minute. Farley played the ball down the right for Ross whose chip went over the head of the advancing Wilkerson, leaving the goalkeeper stranded in the penalty area. It looked as though the shot would go wide but Steve Morris who had made a lot of ground slid in and made enough contact to turn the ball over the line.
Slough came back strongly but it was Southport who went closest to extending their lead when free kicks by Gamble saw Ross and Formby both go close.
Southport were given tremendous support by their travelling fans and held on for the vital lead to take into the second leg.
Southport Line up
Billy Stewart, Paul Futcher, Andy Farley, Tim Ryan, Brian Butler, Ged Kielty, Dave Thompson (Joe Morgan), David Gamble, Kevin Formby, Brian Ross, Stephen Morris (Paul Mitten). Sub not used: Paul Clarke.