Bognor are without a win in four games after Kadell Daniel's 86th-minute finish condemned them to defeat at Margate and left them down to ninth in the table.
It further dims their hopes of making the play-offs although the top half of the table is still very tightly packed as they contemplate going to Enfield next week and trying to get a result.
Doug Tuck was missing along with Jimmy Muitt, while young striker Ollie Humphries got a call-up on the bench after scoring for fun for the club's under-19s.
In a lively start Theo Widdrington tried to find Joe Tomlinson but bounced out of play. Mason Walsh won a free-kick but Harvey Whyte's cross was poor. On the counter for Margae, Tobi Sho Silva passed to Noel Leighton who shot over. George Brown got a shot away as he turned inside the box but it was well gathered by Dan Lincoln, this following good work from Sho Silva.
Louis Wells denied Widdrington with a low strike from outside the box after good work from Whyte and Richard Gilot. Harvey Read headed out Jack Paxman's dipping cross before referee Kirsty Dowle gave Margate a free-kick inside the box. Daniel curled his chance over the bar. Walsh cut across the defence before shooting straight into the arms of a grateful Wells on 20 minutes.
Widdrington's long-range free-kick hit a Margate player before bouncing out for a corner. Then Bradley Lethbridge was shut down following Whyte's ball in. Daniel sent another chance over with his left boot before Paxman's cross was palmed out by Lincoln.
Lincoln pushed Daniel's curling 34th-minute free-kick on to the crossbar and out before having to punch the following corner clear. Silva was blocked by a brave Read on 36 minutes. Walsh's cross was searching for Lethbridge but Paxman got to it. Lethbridge got to a Widdrington through ball but his curling effort was well stopped by Wells on 42 minutes.
Daniel's cross found Silva in the box but he knocked it wide when he should have done better. As the half time whistle went, Bognor would have been happy with how they had defended but would need to up their game in the second half. HT 0-0
Lehtbridge did well to beat his man on the left before getting the ball into Chad Field who poked it at goal, forcing Wells into a reaction save - Bognor's best chance so far. Daniel stole the ball off Field before running and shooting wide. Brown struck another chance at goal but Lincoln was well placed to save.
Leon Maloney made good ground before squaring to Walsh, who took his time before curling the ball well wide on 50 minutes. On 53 minutes Tom Mills' throw saw Jordan Robins fire into the box but Brown headed wide. Daniel got on the end of a high hanging cross but poked it wide in a let-off for Bognor on 55 minutes.
Joseph Hungbo came on for Brown and he soon smacked his low long-range strike wide. Keaton Wood received a booking for a challenge as the Rocks tried hard to contend with the counter-attacking of the Gate. Whyte did well on the right before curling the ball on to the head of Lethbridge, who couldn’t direct his header on target.
Daniel hit another free-kick high and wide from long distance as Margate wasted another opportunity. Straight from Wells kick, Silva brought the ball down for Leighton, whose attempt was always rising over the bar on 72 minutes. Lethbridge's run saw him win a free-kick just outside the area. Widdrington's strike crashed low into the wall and his second attempt was also diverted.
Hungbo forced a decent diving save from Lincoln on 78 minutes after Whyte went into the book for complaining to the linesman. Tomlinson went to ground clutching his left foot but did return to play after treatment. Maloney was replaced by Tommy Scutt on 82 minutes as the Rocks sacrificed a forward player for a midfielder.
Liam Friend spun his header over the bar from Hungbo's corner from the left. Hungbo forced Lincoln into a save and the rebound was cleared off the line by Field. But a goal always felt possible and Margate took the lead on 86 minutes. Daniel worked his way down the left before running inside and shooting low into the bottom corner with a fine strike.
There was no time for a Bognor reply and the defeat was a further blow to their promotion hopes. The Rocks make the trip to fifth-placed Enfield Town next Saturday.
Rocks: Lincoln, Whyte (c), Tomlinson, Read, Field, Wood, Maloney (Scutt 82), Widdrington, Lethbridge, Gilot, Walsh. Subs not used: Sanders, Humphries.
Attendance – 503