Holbeach United missed another chance to close the gap in the title race.
A top-five finish always looked more likely than a championship challenge - even with games in hand.
The Tigers’ promotion bid was effectively ended on Wednesday night by a second 1-0 defeat in 12 days to Cogenhoe United who recorded a seventh successive win.
The performance was better than in the away defeat - but Holbeach again showed a lack of quality.
A one-man advantage for 50 minutes failed to make any difference.
Montel Dore’s goal midway through the first half proved enough, despite a red card for Liam Tuck following an off-the-ball incident when he struck out at Adam Jackson.
Mitch Griffiths and Lewis Leckie hit the crossbar but Cooks number one Stuart Lutter was never tested.
George Barnell’s brilliant last-gasp challenge denied Leckie who fired straight at Lutter just a couple of minutes later.
Lutter kept out Griffiths and Luke Avis after the break but Holbeach looked desperate as they finished the game with five up front.
There was no way back from the moment when Dore found space inside the box and a cross-shot bounced into the net off the far post.
Tuck’s dismissal offered hope for Holbeach but a change of formation didn’t bring a series of clear-cut chances.
Instead, the Tigers were left to reflect on what have been as they again failed to overturn a deficit.
4-3-3: Drury; Harker (sub Keeble 88 mins), Braithwaite, Cartwright (sub Zuerner 60 mins), N Jackson; Griffiths, Tinkler, A Jackson; Bird, Leckie, Barker (sub Avis 78 mins). Sub not used: Warfield.
4-1-3-2: Lutter; Melling, Barnell, Stevenson, Inwood; Chipchase; McBride (sub J Gartland 83 mins), Tuck, Dore; Long (sub Ansell 76 mins), Dove. Subs not used: Johnson, Brazier.
Dore (23 mins, 0-1).
Tuck (violent conduct).
Dove, McBride, A Jackson, N Jackson, Braithwaite (fouls); Griffiths, Melling (unsporting behaviour).