The East Sussex side have been taking part in The Non League Challenge Trophy run by Hooper and Son (@CPriday).
Fans vote for their favourite teams in the matches and the sides with the biggest percentage of votes win.
And on Sunday night Simon Colbran's Wanderers beat North Shields Athletics by the tightest of margins - 50.2% to 49.8%.
They face Marshalls FC in the semi-final. The only other Sussex side to reach the quarter finals were AFC Ringmer, but they lost 3-2 to Cherry Hinton.
Cherry Hinton will play Wallington in the other semi-final.
More than 3,000 teams have entered the competition.
Colbran has been enjoying watching the games as they happen. He said: "It’s been brilliant actually feeling like you are playing in a game, and having the buzz to try and get a result.
"It’s just getting that winning feeling back makes it worth it.
"For a club our size it’s been massive for us, it’s so nice that people have been voting for us and shows clubs our size can achieve anything with a little bit of support."
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