The Rocks thrashed promotion hopefuls Welling United 4-1 on East Monday and thought they were still alive in the National League South survival battle.
But Hungerford’s late winner at champions Torquay United saw the Essex club fall.
They can now only get 39 points and could have stayed up if they beat Hungerford on the final day.
But thanks to the Crusaders’ late joy at Plainmoor, East Thurrock’s joy turned to agony.
But classy Coventry was quickly on his phone and sent a congratulatory tweet to Ian Herring after their incredible result at Torquay.
He said well done for keeping his team up - although Herring was quick to point out they still need one more point to secure survival.
If they draw against East Thurrock on Saturday then it will be Truro City who go down with Weston-super-Mare and Coventry’s team.
But they may not even need that. If they White Tigers don’t beat Slough Town it doesn’t matter what happens at Hungerford.