Tranmere's hopes of staying in League One were dealt a severe blow after a 2-0 defeat at Leyton Orient on Saturday.
The result means Rovers now find themselves in the relegation zone at the worst possible time, with survival in the league going down to the final game of the season at Prenton Park.
Tranmere conceded shortly before half time and despite improving early in the second half, a long range strike from Chris Dagnall sealed the points for the hosts.
Promotion hopefuls Leyton Orient took the lead a minute from the half time whistle.
Matthew Pennington had blocked a shot from David Mooney and Scott Cuthbert's header from the corner was saved by Fon Williams. But Kevin Lisbie reacted quickly to turn in from close range.
Orient's second goal came on 76 minutes. The hosts pressed and forced Steve Jennings to play the ball back to keeper Fon Williams.
His clearance landed at the feet of former Rovers striker Chris Dagnall, who fired a shot into the empty net from 35 yards.
Caretaker manager John McMahon blamed "silly defensive errors" for the defeat as Tranmere dropped into the bottom four.
In his post-match interview, McMahon said: "It's been like that all season.
"I can't legislate for mistakes like that.
!I can set teams up, look at systems and shapes but what I can't do is stop silly mistakes from happening.
"We switch off and get punished from the corner. I can't do anything about that.
"We haven't dealt with a lot of things all season. We can play all the football we like and create chances, but when you can't do the simple things well defensively you're going to suffer.
"If you don't score goals you're never going to win football matches.
"It's worrying. We're creating chances, it's being in the right places and being clinical to take those chances."
McMahon was full of praise for the club's supporters: "The fans have been fantastic again.
"They gave everything they've got so I'm never going to criticise them.
"If they're going to do any moaning, let it be at me and not at the players because it's the last thing they need.
"We need to win now and it's out of our hands, but that's the way it is.
"We've got to regroup, we've got to refocus and the only thing we can do is win our home game next week."
The result placed Tranmere in the relegation zone on 47 points, one behind Crewe who sit above them in the table.
Rover's final game of the season will be played at home on Saturday against Bradford.
Kick-off at Prenton Park will be at 3pm.