Horsham were put to the sword in a devastating 20-minute first-half spell which saw promotion-chasing Corinthian Casuals complete a comfortable victory.
The Culver Road visitors narrowed the gap on Bostik League South Division leaders Lewes to three points while leaving the Hornets winless in four with their 4-1 success.
Player availability was again an issue as Dominic Di Paola named just three substitutes with Darren Boswell, Joe Shelley and Alex Duncan all missing from the side that drew 1-1 with East Grinstead as an illness bug swept the squad - with Hakeem Adelakun also out.
Goals from Reyon Dillon, Gabriel Odunaike and Max Oldham put Casuals in early control and that is how it remained at half-time.
Hamilton Antonio made it 4-0 on the hour mark as the away side continued where they left off, but while they failed to extend the scoreline further a bit of late Horsham pressure saw Toby House grab a consolation goal.
Di Paola bemoaned individual mistakes for the goals and said: “We just did not turn up. I think the boys turned it around a little bit in the second half with a better approach.
“We had a bit of a flu problem with Darren, Joe Shelley, Hacks (Adelakun) all out, and Wezzo, Jack Newhouse and Josh Street have all had it, but there are no excuses. Mistakes gave them their goals and they did not have to do much to beat us. It was a horrible night in general, quiet, cold and we just did not get going.
“We showed a bit of fight in the last 15 minutes and could have had two or three goals, but they had taken their foot off the gas. They were just clinical and you can see why they are doing well. I said to the boys at half-time, our mistakes kill us as, all four goals came from our errors.”
Horsham: Daly, Hyde, Boiling, Farmer, Metcalf, Hartley, Kirkwood, Street (Axell 46), Nwachukwu (Newhouse 75), House, Bown (MacDevitt 65).