Margate, favourites to win the Isthmian League, Premier Division this season, had the better of the opening ten minutes or so, with former Gillingham man Charlie Allen seeing a shot whistle over the bar, and Lewis Taylor having a shot well saved.
With a quarter of an hour played, Slough took the lead with their first attack. The ball fell to Jamie McClurg at the back post, and he stretched to get an effort in on goal, which deflected in off Brett Johnson.
Just eight minutes later, Slough doubled their lead, with the away side capitalising on a defensive slip. Eddie Smith squared the ball to his strike partner Scott Harris, who duly struck the ball low into the right hand corner of Nikki Bull’s goal.
Margate struggled to create chances against a resolute Slough side, playing three centre-backs and three central midfield players to combat the Blues’ diamond formation, but came close to pulling a goal back late in the half as a header from Tom Phipp, which looked to be goalbound, struck Ryan Moss, who nodded the ball over from close range.
Both sides were hampered with injury concerns, with McClurg forced off with an injury on 36 minutes to be replaced by Jake Parsons, and on the stroke of half time, Margate’s chances of getting back into the game worsened when talisman Allen was stretchered off after taking a blow to his chest.
Early in the second half, Smith saw a shot blocked by the Margate defence as the ball fell kindly to him, and minutes later, Reece Yorke saw a header cleared off the line.
Margate continued to labour against the Rebels, and Lewis Taylor could only divert a Luke Williams cross wide of the post.
Eddie Smith, on a fine run after a hat-trick at Biggleswade on Tuesday, was unlucky not to get his name on the score sheet here, having one effort denied by an offside flag after seizing upon Luke Knight’s shot, and then having another shot deflected inches wide. From the resulting corner, Billy Jeffreys had a header cleared off the line by Taylor as Slough looked the more likely to score.
In the final fifteen minutes, the hosts mustered chances to get back into the game, but Ryan Moss headed over the bar and Jamie Stuart flicked wide from a corner.
A better chance arrived for Taylor, who saw an effort bundled behind by Aleks Gogic after good work by right full-back Tambeson Eyong, but Slough held on to progress to the next round.
Margate Line up
Nikki Bull, Tambeson Eyong, Anthony Rivière, Charlie Allen (Kane Wills), Jamie Stuart (c), Brett Johnson, Lewis Taylor, Luke Williams, Ryan Moss, Zac Attwood, Tom Phipp (Jamie Taylor). Subs not used: Luke Moore, John Beales, Freddie Grant.