Bognor succumbed to their first defeat of the season as they battled without some key players in Essex but couldn't score in a game to forget at Rookery Hill.
Rocks manager Jack Pearce was without Ollie Pearce with a groin injury and Alex Parsons was also missing. Doug Tuck, Jimmy Muitt and Corey Heath were all still out injured.
Lewis Smith was causing early problems on the left for ET and eventually the ball fell to Sam Higgins but his cross was powered out by Sami El-Abd in the Bognor area.
Ben Swallow worked his way down the right to cut back the ball to Pat Suraci and his chipped pass bounced through to the goalkeeper harmlessly on seven minutes during a slow start.
El-Abd let Reece Harris' cross bounce out for a goal kick as East Thurrock quickly were on the attack with Higgins and Femi Akinwonda.
East Thurrock went ahead on 12 minutes as Smith got beyond the Bognor defence before crossing into the middle of the area where Montel Agyemang pounced to slot home from close range.
Harvey Whyte got a talking to after clashing late in the air with Harris on 16 minutes. Lewis passed to Max Cornhill but his through ball had too much power and rolled off for a goal kick.
Whyte smacked one over the bar on 20 minutes following a ball in from the left. El-Abd played a pass to Calvin Davies, who was beaten to the ball by Lewis and he ran through and hit a deflected shot off a Bognor defender and low into the arms of Dan Lincoln.
Akinwande worked hard on the left to pass square to Agyemang, who in turn passed to Cornhill. The midfielder smacked one from the edge of the box but the ball bounced back off the crossbar on 26 minutes.
Dan Beck was late with a challenge on Simon Peddie but Akinwande's ambitious low shot bounced wide of the left post. Good play started by Swallow allowed Davies freedom on the right but his cross was struck over the bar.
A long ball over the top by Davies was stopped by goalkeeper Lukas Lidakevicious with Whyte in pursuit on 33 minutes. A left footed attempt by Akinwonda was blasted over the bar after a neat cross by Higgins.
Suraci's shot ricocheted off a defender before Beck hit one with his first touch which spun high and wide of the goal. Higgins had the ball in the net again on 42 minutes but the goal was dissallowed for an offside decision.
Bognor worked the ball forward to Jimmy Wild who appeared to be isolated up front during the first half. He turned and stubbed a shot harmlessly wide on 43 minutes. Harris beat his man before chipping a cross in for Cornhill who spun his header high but Lincoln gathered it in the air. Higgins struck another from a tight angle in the box but Lincoln denied him right at the end of the half.
It got worse for Bognor early in the second half as after only 47 minutes a free-kick on the right was curled in by Harris and Higgins beat his marker to head in at the near post, giving the hosts a 2-0 lead.
Davies won a corner on the right. The short corner by Suraci to Swallow saw the latter cross it into the area and James Crane diverted it wide on the volley. Whyte combined with Swallow on the right and his cross found Crane on the back post and his header back into the area was cleared out again.
Tommy Block received a yellow card on 53 minutes.
Higgins got past his marker after a through ball and had a go but his effort came back out off the left post. Akinwande passed to Harris, who hit it from distance but it swung the wrong side of the goal on 57 minutes after good play from the hosts, who were giving Bognor's defence much to think about throughout.
Wild held the ball up for Davies on the right. He played the ball back to Suraci in the box but his instant attempt was blocked bravely by the hosts defence on 63 minutes. Agyemang hit one straight at Lincoln before Davies's cross had to be pushed over the bar by the opposing goalkeeper.
On 70 minutes East Thurrock had the ball in the net. A foul was ignored and Akinwande rounded his marker before shooting low beyond Lincoln, who had got something to it before the ball flew in. However, the referee disallowed the goal and pulled it back for a free-kick after speaking to his assistant who witness a foul in the build up.
El-Abd was tripped late by Smith before Tommy Cooney - who had signed for the Rocks a day earlier - replaced the ineffective Wild on 74 minutes. Smith came off for Kye Ruel on 76 minutes for the hosts. A through pass to Higgins saw him shoot but it bounced well wide of the goal. Block was replaced by Joe Lea on 77 minutes.
Peddie was booked for complaining and wasting time on 80 minutes. Swallow was trying his best on the left and hit a cross in from the byline but the ball ran out of play as it really wasn't Bognor's day.
Tommy Scutt replaced Beck on 86 minutes and Agyemang went off for Ryan Boswell for the hosts. A Davies corner was struck straight at the goalkeeper before East Thurrock were caught offside on the break.
Harry Honesty came on for Akinwande inside stoppage time. Bognor's last chance saw Cooney cross it but the goalkeeper cut the ball out.
This was a game to forget for Bognor, who welcome Eastbourne Borough to Nyewood Lane on Bank Holiday Monday, 3.00pm kick off.
Rocks: Lincoln, Davies, Crane, Block (Lea 77), El-Abd, Field, Whyte, Beck (c) (Scutt 86), Wild (Cooney 74), Suraci, Swallow. Sub not Used: Boughton (G/K)