A second-half collapse by ten-men Selsey saw them go down 4-1 at Ringmer - and Ian Martin’s side were pushed down to 16th in Sussex League division one as a result.
After an own goal from the home side had put Selsey 1-0 up, Max Thoms was sent off just before half-time and not even Ben Courtnage’s dismissal late on for the home side could help the visitors.
David Altendorf struck for the home side on 49 minutes, with Marc Whiteman scoring either side of Aaron Phillips’ goal in the 89th minute.
Still nine points clear of the relegation zone, Selsey now look ahead to Saturday’s home tie against Peacehaven.
Martin said: “The sending-off was ridiculous and it’s annoying because we’ve been playing really well now for a few weeks and we started that game brilliantly.
“We had to re-organise because the sending-off left a massive hole in the middle of our midfield, and I don’t want to praise Ringmer because I feel it’s another game we should have won.
“I can blame the referee but as a team they can’t - the bottom line is goals win games. We’ve just got to work on that in training.”
And after conceding seven goals in the past two matches, Martin said: “I’ve said before about strikers needing to take their chances and we’re just not doing that at the moment.
“We created loads of chances and when you don’t take those it puts pressure on your defence.
“Defending set-pieces is a problem of ours – we’re a small side and there’s only so much you can do in those situations. We have to stop giving away those chances for teams to deliver long balls into the area.”
The dismissal in Selsey’s tenth defeat of the season brought the club’s card count to 36 yellows and eight reds this season, and Martin acknowledges work may need to be done.
He said: “It’s certainly a concern for the chairman and I take those on board but the past couple have been very unfair.
“I think it’s been a while since we’ve had a sending-off that’s been down to ill discipline or petulance. The Max Thoms one on Saturday wass just two competitive challenges - that’s all he was guilty of.”
Peacehaven are ninth in the league table, and Selsey will be hoping to record a more positive result in their last game before Christmas to reinstate the feelgood factor at the club Martin spoke of last week.
“There’s no reason that should ebb away after just one poor result,” he said.