Elliott Powell suffered his first defeat as Jersey Bulls manager as his side conceded two late goals to lose 2-1 at Whitstable Town in the FA Vase.
Powell, who took over the islanders in the summer, had been unbeaten in 20 league and cup matches.
It looked as though he would extend that record to 21 games after Francis Lekimamati gave Bulls a 13th-minute lead.
But Josh Oliver converted an 84th-minute penalty before Nico Grierson got the winner two minutes later as the Southern Counties East League Premier Division side reached the third round.
Bulls’ day was made worse as they had forward Rai Dos Santos carried off after an hour to add to their injury woes while Sammy Sutcliffe was sent off in stoppage time for a late challenge.
“The penalty was a little bit soft, but it felt inevitable after that unfortunately,” Powell told BBC Radio Jersey.
“They put just a little bit too much pressure on us and probably for the first time this season we looked like creaking, and unfortunately we did.
“It’s not a great day at the office, but at least it allows us to focus on the league.”
Bulls are seven points off the top of Combined Counties Premier South with at least three games in hand on the sides above them.
While promotion is Powell’s objective he says he is disappointed that his side’s hopes of playing at Wembley have ended.
“That carrot of Wembley is tantalising and you want to be that step closer every single time,” he said.
“I thought it was quite a favourable draw for whoever got through this one, so it is a frustrating one.
“But the priority from the board and from the club has been the league campaign and getting out of step five.
“We need to focus on that now, we’d like to have been attacking on all fronts, but it’s not to be and we need to dust ourselves down and go again.”