Robbie Blake was left frustrated after Bognor failed to turn chances and possession into goals in their 2-1 defeat at Haringey Borough.
The Rocks’ push for the play-offs suffered another dent despite a battling performance in gale force winds which shaped the contest.
Bognor fell to a sucker-punch 82nd-minute goal by Anthony McDonald at Coles Park after a goalless first half.
Haringey took a 47th minute lead when Georgios Aresti’s low shot beat Amadou Tangara.
Rocks levelled after 61 minutes when Harvey Whyte peeled off his marker in the box to head home Tommy Leigh’s corner.
Hopes of a win evaporated when McDonald slammed home after Roman Michael-Percil initially had penalty claims waved away after going down on the edge of Bognor’s area.
Coach Blake said: “We have had so many chances and ended up losing to a team who have had two chances in the game.
“It’s the story of our season. We haven’t been strong enough and resolute enough defensively, that’s the crux of it and it has cost us again.”
He added: “I can’t fault the commitment and attitude and I felt we played really well and never in a million years should we have lost the game.”
He continued: “We got into so many good positions in the final third and we blew it.
“We lacked composure and belief and that is very frustrating.”
Blake was impressed with the way Bognor tried to manage the conditions, especially in the second half when Haringey had the wind behind them.
Rocks handed a first start to recent signing Tresor Shema, while defender James Crane was back on the bench after being away on a work-related trip.
Kristian Campbell, who has had a previously successful stay at the club during their National South days, has re-signed and will be available, having watched from the sidelines on Wednesday.