Needing to win and pray that both Leicestershire and Derbyshire succumbed to Lancashire and Gloucestershire respectively, only the second of these came to pass.
The outcome means that the County’s season is effectively over with just the four LV= County Championship outings remaining and relegation back to the second tier a virtual certainty.
There has plenty to take from the 50-over excursions - more than from the 20-over outings for sure - but more work will need to be done if they are to become a force when the competition resumes next year.
Essex’s preference is to chase as opposed to set a score and after Mark Pettini called correctly on an autumnal afternoon, and gave the hosts first use of an excellent surface, they were given a decent total to pursue.
It could have, and definitely should have, been a bit better than the 311 which was finally realised as three overs were sloppily unused but after a season of misfiring batting efforts in the white ball formats, this was a lot more like it.
And it was David Willey who dominated the first half of the contest with an excellent 113 - his second century in List A cricket - that further highlighted his destructive capabilities with bat in hand.
Scoring freely on both sides of the wicket and with the enviable quality of being able to hit the ball out of the ground, Willey was relatively circumspect as he strolled to 50 from 46 balls but he opened his shoulders to some degree in the latter stages of his stint.
Having entered the fray in the 19th over, Willey put Richard Levi in the shade in a fourth-wicket stand of 114 with the latter’s contribution a paltry 27.
The fact Levi made 84 at almost a run a ball, and Rob Keogh a 39-ball 50, was overshadowed by Willey’s performance and it was a pity the left-hander was out with six overs to go as it spelled the start of a late collapse that saw the last five wickets fall for 13 runs.
Earlier in the piece, Levi and Keogh comfortably, and with no risk, compiled 100 for the first wicket in under 15 overs to lay a solid foundation for Willey to exploit.
The Essex reply, led by the in-form Westley, was up and running straight away and by the time Matt Spriegel hit him in front in his first over, the 16th, for 62, 94 had been erased from the target.
Pettini, dropped at cover off Graeme White on 35, raised his own tempo once his partner had departed and he coasted to the second half century of the innings as the required rate was maintained with little fuss.
Along with Ravi Bopara, who would go on to record the third half century of the chase, the duo eased their side into a strong position and the losses of both Pettini and Jaik Mickleburgh were comfortably absorbed.
But when Kishen Velani and Bopara were dismissed within a few minutes of each other the task for Essex became a touch trickier but although James Foster became the sixth wicket to fall, the winning line was crossed with three balls remaining.