Tom Kavanagh's 87th minute free kick clinched a 1-0 win over National League premier side Woking to spark great scenes at the Camping World Community Stadium, in front of a bumper crowd of 1,927. See the winning goal here.
Horsham fans and football followers from further afield have been all over social media expressing their delight at the win and responding to the club asking them: Who do you want next?
Comments about the victory on Twitter included:
Eddie French: Get in fellas! Love this. Epic result. Enjoy tonight @LardyArmy and all players & staff. In the hat again.
Trillo: I'm a Woking fan and would like to congratulate you on what was a fantastic performance, fully deserved. Was an absolute stunning goal. I shall be keeping a close eye on the draw and wish you all the best!
Alexis Conway: Been to a few underdog @EmiratesFACup matches over the years but @HorshamFC were on form today. Stayed solid against a strong @wokingfc side.
Phil Reeves: Jack Brivio go on lad! Congratulations, could have a massive game next round!
FA Cup Factfile: Congrats on your terrific two level #FACup #Cupset 1-0 victory today and on reaching the 1st Rd for the first time in 15 years.
Mark Murphy: Fully deserved against a much bigger ( except in heart) team. Hung in there when the pressure was on and did the job! Tommy Kavanagh, just like his grandad Eddie, is an FA cup legend!
Danny Wootton: Well done folks. Lifelong Crawley fan but have always had a soft spot for the Hornets harking back to the Queen Street days when I worked locally in the 1990s.
Preston Park FC: Congratulations on your win today it's what the FA Cup is all about and hopefully you get a decent draw for the first round.
See scenes from the end of the famous victory in our video by Sam Pole, in the video above
Comments on who fans would like the Hornets to play in the first round - which is on the weekend of November 6/7 - included:
Charlie Hempstead: Argyle away will do me just fine.
Josh: Sunderland or Portsmouth at home.
Arun: Sunderland away please.
Ben Wright: Charlton away