The Rocks failed to build on a dream start in their FA Cup tie with AFC Sudbury - and ended up having to settle for a replay.
Harvey Whyte seemed to have set them on their way to the third qualifying round with a third-minute goal - but Sudbury levelled eight minutes later.
The Rocks had the vast majority of the possession after that and launched attack after attack - but their final ball into the box and their shooting let them down and it ended up as an afternoon of some frustration.
Bognor's commanding 5-0 win at Whitstable in the first qualifying round earned them £6,000 and there was a £9,000 prize pot up for grabs in this second qualifying round tie.
The Rocks were without young Pompey forward goalscoring duo Dan Smith and Brad Lethbridge, both apparently carrying minor injuries. That left Jimmy Muitt - fresh from his four goals in 15 minutes against Whitehawk on Tuesday - and Mason Walsh to share forward duties.
Sudbury arrived at a rainy Nyewood Lane on the back of a difficult start to the season that had left them 14th in Bostik North - the league below the one Bognor play in. But in the back of Bognor minds will have been the memory of Subury knocking the Rocks out of the 2014-15 FA Trophy in a replay after a draw in West Sussex.
See coach Robbie Blake's verdict on the game in the interview, above
The Rocks had a dream start with the opening goal in the third minute as a Sudbury player headed the ball straight to Muitt on halfway and he surged forward, releasing the unmarked Whyte to take a touch and sidefoot in.
Sudbury midfielder Jordan Blackwell went into the book for a late challenge on Chad Field as the Suffolk visitors struggled to get a foothold.
Bognor were back on the attack on eight minutes when Muitt and Walsh played in Joe Tomlinson for a low shot that skidded off the wet turf but was saved well by Paul Walker.
Sudbury levelled on 11 minutes as Callum Harrison nodded in a loose ball after keeper Dan Lincoln failed in two attempts to gather a high cross into the six-yard box.
An interchange between Calvin Davies and Whyte down the right led to the full-back's cross being pulled back for Doug Tuck 10 yards from goal but he miscused his shot.
Tomlinson was proving quite a goal threat and a curling effort on 23 minutes from more than 20 yards forced Walker into a diving save with Whyte lurking and looking for a loose ball.
Two minutes later Muitt raced away again but was forced to check his run. Eventually he played it to Tuck, whose return pass led to Muitt curling a shot on target that Walker held.
Just before the half-hour Reece Harris was booked for a foul on Davies that gave Bognor a free-kick on the byline just outside the area on the right. That eventually fell to Tuck, whose cross was headed over by Field. It was Field's central defensive partner Keaton Wood's turn to head over on 35 minutes from a Muitt corner.
A floated Whyte cross might have brought a very rare headed goal from Tuck but he couldn't get it on target. Then Muitt curled in a cross for Whyte but his header was straight at the keeper from close in.
Walsh and Muitt led another Bognor charge but Walsh was well tackled just as he was about to shoot in the D. Tomlinson drove another dangerous cross into the danger area from the left but Sudbury got back in numbers. Then Tommy Scutt fired a shot over from a tight angle.
Scorer Harrison tested Lincoln from 30 yards in the first minute of the second half. Davies earned a booking for dissent seven minutes into the second half for arguing with a soft decision against the hosts. A Muitt corner fell to Scutt but he was leaning back as he hit it from 15 yards and it flew well over the crossbar.
There was a real scare for Jack Pearce and Robbie Blake's team on 56 minutes when Ben Hunter curled a 25-yarder over Lincoln and it came back off the bar.
Bognor's play was becoming increasingly frantic and, for the fans, frustrating. They were having plenty of attacks but were losing the ball all too easily before getting into dangerous areas. Sudbury were a threat on the break and Hunter worked his way into space only to shoot straight at Lincoln.
For Sudbury Paul Hayes replaced Harris on 64 minutes.
For a while the whole game was being played in the Sudbury half, but the Rocks were failing to trouble the keeper.
Young striker Josh McCormick was handed his chance to be a hero, replacing Scutt with 19 minutes left. Sudbury brought Kelly off and put Isaac Skubich on in his place.
Whyte and Davies teamed up down the right but Davies' shot was always going wide.
The Rocks kept finding space for crosses - and kept finding the first defender with them. The crowd were becoming increasingly agitated as a result and that six-goal burst against Whitehawk suddenly seemed a distant memory. A better ball in across goal from the left eluded three Rocks players who had got forward.
A third Sudbury change saw Thomas Dettmar replace Hunter. Block followed Davies' bad example with a booking for dissent after a free-kick was given to Sudbury.
A better Rocks move saw the ball moved across the area to Tomlinson, whose shot was deflected behind for yet another corner. Another Rocks chance fell to Davies but his fiercely-hit shot was high and wide. Whyte was named MoM for an energetic performance.
Sudbury nicked possession in the Bognor half and Harrison chanced his arm from long range but it was straight at Lincoln - but the chance showed they were still a danger. Harrison was booked in injury time for pulling Whyte back by the shirt.
Charlie Osborne came on for Block in the third minute of injury time. Osborne was immediately booked for a tackle that gave Sudbury a free-kick 30 yards out. The kick was fired over - and that was that, meaning a replay will be needed on Tuesday evening in Suffolk, with the Rocks hoping to avoid the fate that befell them in the Trophy four years ago.
Rocks: Lincoln, Davies, Tomlinson, Tuck, Field, Wood, Whyte, Block, Scutt, Muitt, Walsh. Subs: Heath, Osborne, McCormick.
Sudbury: Walker, Altintop, Coakley, Holland, French, Whight, Blackwell, Hunter, Kelly, Harrison, Harris. Subs: McKenzie, Hayes, Sayer, Dyer, Dettmar, Skubich, Whiteman.
Ref: James Robinson