Slough started brightly and forced a good save from the home keeper. A long throw from Steve Dell was flicked on at the near post by Adam Wallace with Steve Daly getting on the end of it at the back post. The keeper parried the ball out and Leigh Mason's shot was blocked.
Nathan Miles went close at the other end before a looping overhead kick from Jamie Jarvis went narrowly the wrong side of the bar.
The home side opened the scoring with twenty four minutes played. A deep cross from the right back position looking for the run of Steve Mesher was misjudged by Kieron Drake and the keeper could only divert the ball to Mesher who was then able to convert into an empty net.
Slough responded well and within two minutes were back level. Steve Dell crossed in from the right and Adam Wallace contested the ball with keeper Jon Gindre. The keeper spilled the ball and Anaclet Odhiambo squared the ball to Michael Alexis for a simple finish.
Slough should have taken the lead from the penalty spot following an infringement just inside the area. Wallace stepped up to take the penalty, but Gindre guessed correctly and saved comfortably to his left.
Slough did take the lead with five minutes of the first half left. Dell was again involved, feeding the ball in from the right to Odhiambo. The striker laid the ball off to the edge of the area where Jarvis was running in and the defender smashed one low into the bottom corner.
Slough looked more conservative in the second half as they looked to protect their lead but were looking dangerous on the counter and from set pieces.
They were close to extending their lead when a free kick from Drake was flicked on by Wallace. Sub Mark Bartley ran on and crossed from the right. Gindre was only able to parry the cross as it fell to Odhiambo but the striker's effort bounced back off the post and into the arms of Gindre.
A few half chances for the home side missed the target and Slough saw the game out to progress through to the Second Qualifying Round.
Cobham Line up
Jon Gindre, Ryan Anderson, Alin Constaintin, Paul Hicks, Nicky Andrews (c), Paul Durrans, Nathan Miles, Nick Tooley, Mark Knight, Steve Mesher, Oliver Wayne. Subs: Cornell McKay, Rob Wilson, Danny Cox, Chris Evans.