Havant lost 41-10 at Staines as they suffered a huge blow in their fight for National League three London & south east.
The Hooks Lane squad remain rooted at the bottom, 21 points adrift of safety.
With runaway league leaders Canterbury next up, life doesn’t look like getting any easier for Will Knight’s side.
‘The steep mountain we had to climb just got steeper,’ said Knight.
‘We still have winnable games to come but we know this was a game we had to win.’
To make matters worse, the visitors had two players sent off in the final seconds, after the game erupted into an ugly brawl.
Knight added: ‘It is a hugely disappointing result, considering the fact there was only a one-point difference with 13 minutes to go,’ said director of rugby Will Knight.
‘The wheels came off in the final stages after our winger was yellow carded.
‘Up to that point, our performance was good.
‘And in the first half we played some of our best rugby of the season.
‘We threw the ball about well and dominated Staines in the scrummage and line-out.
‘Both teams were trying to play open rugby and it was a very close affair.’
Knowing it was a must-win game, Havant started on the front foot and took a seventh-minute lead.
After a good kick to the corner, Havant produced a well-worked line-out for Dom Bellman to cross for the try, which was converted by Joel Knight.
The hosts hit back to lead 8-7 at the break before both teams knocked over a penalty to leave it tense as they entered the final stages.
A lack of discipline cost Havant dearly, though, as their winger clearly went offside in his own 22 to earn an obvious yellow card, leaving Havant a man short.
The home side wasted no time in exploiting that advantage and raced in three quick tries to take the game away from the visitors.
At the end, Joel Knight took exception to a dangerous tackle and Pete Austin took the law into his own hands as both saw red cards, along with one of the home players.
Knight said: ‘It didn’t help our cause when we lost two wing-forwards at training on Thursday night.
‘Tommy Horn was rushed to hospital where he had his appendix removed and Richard Burgess-Kelly pulled a hamstring.
‘The two lads who came in, though, Dom Porter and Dom Bellman, did a magnificent job and had a big impact.
‘We have to regroup now for a very difficult game next weekend, before preparing for those that are still winnable after that.’