Manager Steve Watt introduced Harry Stannard up front in the absence of Jordan Chiedozie (Suspended) and Jay May (Cup Tied) otherwise it was as you were for the Gate as they looked to progress.
The Blues could have been ahead early on as Orlando Smith was released through the middle but his effort smacked back off the post and away to safety as Margate tried to force the esrly openings.
Kings Langley had to wait until the 37th minute for their first meaningful opportunity and it was one that they was left to rue as Mitchell Weiss raced through but his low fierce effort was well saved by Lenny Pidgeley to deny the hosts a lead.
The second half started very cagey with neither side wanting to concede the first goal as Referee Scott Williams waved away a penalty appeal from the hosts as Tom Mills stood his ground against a lively Weiss.
The frustration was growing for Margate who were being snuffed out every time by a resolute Kings Langley back four who foiled a low Frannie Collin cross before closing down Matthew Bodkin who snatched his effort high and wide.
The visitors persistence paid off in the 59th minute as half time substitute David Martin raced down the left before crossing to Smith who managed to get his foot over the ball and volley the ‘Gate into a 1-0 lead.
That goal was enough to seal the win fpr the Blues but they could have easily doubled that lead in the 70th minute as Tom Wynter rose highest at the back post from a corner but his downward header was hacked off the line.
The host were to end the game with only 10 men as Emmanuel Folarin received a second yellow card for a harsh challenge and the Blues saw out the final minutes to progress to the next round of the Emirates FA Cup.
Margate: Pidgeley, Sessegnon, Mills, Rogers, Friend, Wynter, Bodkin (Brown 77’), Prescott, Smith (Swift 77’), Collin, Stannard (Martin 45’)
Subs not used: Waller, Killick, O’Halloran, Jones