Essex captain James Foster is hopeful his side can reach the semi-finals of the CB40 after Sunday's crushing 118-run win over Gloucestershire.
The win has put the Eagles in a three-way tie at the top of the group, with only one guaranteed to progress.
Foster told BBC Essex: "It was a superb win and keeps us in with a shout of qualifying for the semi-finals.
"I thought the spinners bowled exceptionally well, and maybe that was the difference."
Essex visit leaders Somerset in a potential group decider next Monday.
Before that, the Eagles will also be hoping Somerset slip up in their penultimate group match at Gloucestershire on Wednesday.
Nottinghamshire are the third side in the mix. They must beat Lancashire in their final match and hope other results go their way if they are to qualify.