Heading into the final round, they are among four teams vying for the final two Top Four Cup places with top-placed Inglewood United and second-placed Perth (40 points) already confirmed.
A 3-2 win to Sorrento in a rescheduled fixture against Cockburn on Wednesday night has brought the Gulls to fifth place, equal on 38 points with the Jacks (fourth) and Floreat Athena (third).
Such is the heat of the competition, both teams could finish as high as second with a win or miss the finals altogether with a loss.
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READ NOWAnd it won’t be easy for them, with ECU facing the league-leading Inglewood at Inglewood Stadium and Sorrento opposing potential title winners Perth at Percy Doyle Reserve.
Short of the final fixture falling on a derby between the two arch rivals, the script could not have been better written.
Should ECU lose, it needs Balcatta (eighth) to defeat or draw with Bayswater City (sixth, 35 points) and Perth to defeat Sorrento to prevent it dropping out of the top four.
But conversely, if ECU triumphs, it needs Sorrento to beat Perth and Floreat Athena to not win against Cockburn to snare second place.
Sorrento would finish second if it beats Perth, while ECU and Floreat are not victorious their games.
A loss would most likely have the Gulls miss out, given their inferior goal difference.
Draws for Sorrento and ECU could be enough for them to advance if other results fall their way.
Last weekend, the Jacks moved into the top four from fifth place with a 3-1 win over Cockburn at ECU Joondalup Football Stadium.
They are now unbeaten from 11 games.
Sorrento defeated Subiaco 2-1 at Rosalie Park to stretch its unbeaten streak to five before the win over the Cockerills made it six.