Promotion challengers Crawley Down Gatwick suffered a shock 1-0 defeat at home to third from bottom strugglers Corinthian Casuals.
Going into the game on the back of an impressive one loss in the previous nine matches, the Anvils were slow to get going and only managed one decent shot on goal in the whole of the first half.
Casuals scored what proved to be the winning goal in the 65th minute when Craig Mullen went on a breakaway run and set up James Byatt for a first time strike which beat Down keeper Anthony Di Bernardo.
Ross Morley fired twice at goal for Down, once seeing a 25-yard free-kick tipped over the bar and then in the 90th minute skied another long-range drive well over the crossbar.
Boss John Maggs criticised his players for a poor display lacking in attacking spark.
He said: “Our performance just wasn’t acceptable to me. I’m really, really hurting.
“Some of those players need to go home and take a look at themselves because that wasn’t good enough.
“They think they’ve got a divine right to beat a team like Corinthians who have struggled to win games and just turn up to play.
“There was no urgency about us today and certainly not much football about us. All credit to Corinthian Casuals, they worked very very hard to make it hard for us.
“There’s only four players in my team I can give credit to and the rest of them were poor.
“We were very very poor up front. There was no movement from the three people up front and it was bordering on lazy. They are big players for me, really good players and I’m surprised they put in a performance like that. But it wasn’t only them, it was other players as well.”
Maggs reckoned this display could end up runing what has so far been a promising season for the club in only their second Ryman League campaign.
He said: “The club has put itself into a wonderful position where we can challenge for a play-off place and we could throw it away with a performance like that.
“The boys think it’s an easy game against a team struggling to pick up a point or two. It’s a mind thing, it’s always happened in football. I don’t mind losing if we play well, but when you get kicked in the teeth like that I honestly can’t accept it, sorry.”