Burgess Hill Town suffered last minute heartbreak as substitute Danny Harris’ strike saw them lose 2-1 to Dartford at The Green Elephants Stadium.
Hill had been comfortable for most of the game and more than matched their Conference Premier counterparts.
A replay looked the most likely outcome after an even second half but a rare lapse in the Hillians’ defence let Harris in who beat Josh James with a low drive.
The Hillians looked lively from the kick off and skipper Darren Budd had the first chance after two minutes but his 20 yard effort just went over.
But after just five minutes the home side found themselves behind. Dartford broke into Burgess Hill box and Tom Bradbrook drew a clumsy challenge from Sam Fisk and the referee had no hesitation in pointing to the spot.
Josh James dived the right way but he couldn’t stop Harry Crawford’s penalty.
Burgess still seemed in control though and on 12 minutes produced a good break through skipper Budd, who played in Lee Harding down the right but his low cross was blocked for a corner.
Budd seemed to be at the centre of everything for Hill and on 16 minutes almost equalised when his powerful volley stung the hands of Dartford keeper Ibrahim.
From the resulting corner Dartford half cleared the corner to Dan Pearse, but his rasping drive flew well wide.
Dartford ‘s next foray into the box saw Bradbrook cut the ball back to Ryan Hayes, whose curling shot found Bradbrook at the back post - but he somehow missed from a yard out. But to his relief the linesman had flagged him offside.
The Hillians were getting a lot of balls into the Dartford box but keeper Ibrahim seemed to be holding onto everything.
And on 28 minutes Josh James spilled a low cross from Lee Noble but Bradbrook couldn’t take advantage and shot wide.
Mistakes started to creep in both sides but neither could take advantage on a heavy surface which was holding up well.
But on 39 minutes Hill got a deserved equaliser when Pat Harding followed up Dan Pearse’s drive from 25 yards which Ibrahim saved but could not hold on to.
It was the least Burgess Hill deserved.
Burgess Hill started off the brighter in the second half and Joe Keehan drove over the bar from 20 yards out.
Dartford should have gone ahead on 56 minutes but somehow Will Miles blocked on the line after a crazy goal mouth scramble.
Hillians had their chances to and Ibrahim was forced to make a great save from Keehan on 85 minutes after Dan Perry pulled back to him.
But just as a replay looked likely, Harris put Dartford through.
It will be a bitter pill to swallow for Ian Chapman and his men but they can now focus on the league and that incredible unbeaten run.
Burgess Hill: Josh James, Neil Watts, Sam Fisk, Darren Budd (captain), Andy Pearson, Will Miles, Dan Pearse, Joe Keehan, Pat Harding, Lee Harding, Rob O’Toole.
Subs: Graham Martin, Spencer Slaughter, Callum Saunders, Toby Pointing, Dan Perry
Dartford: Deren Ibrahim, Lee Burns, Callum Driver (captain), Rory McAuley, Mat Mitchel-King, Ryan Hayes, Peter Sweeney, Lee Noble, Max Cornhill, Harry Crawford, Tom Bradbrook
Subs: Danny Harris, Luke Daley, Nathan Collier, Ebrima Adams, Tony Kessell (GK)