FLEET were boosted by the rare sight of a huge crowd, 1,173, at their Ship Lane home and fought their illustrious visitors all the way.
But an 85th minute goal saw the host’s relegation worries increase when they lost 1-0.
With ex Canvey boss Jeff King’s Chelmsford City suffering another defeat, 2-1 at second-from-bottom Bognor Regis, Wimbledon are now nine points clear at the top and looking an odds-on bet for claiming the only automatic promotion spot.
Thurrock remain third from bottom but will surely escape the drop if they can consistently continue the effort and commitment shown in this defeat.
With ex-Billericay defender Rob Swaine in top form at the heart of the home rearguard, Fleet withstood all that the visitors could throw at them early on.
Then the hosts launched into attack themselves and created three good chances through David Bryant, Craig Hughes and Sam Lechmere.
The visitors continued to dominate the possession after the break, but Fleet again looked more dangerous when they attacked.
Bryant went close with a flicked header from home debutant Lorcan Fitzgerald’s free-kick, but Wimbledon grabbed a fortuitous winner five minutes from time.
Swaine was harshly penalised for a foul when he appeared to make a clean tackle and Jake Leberi’s free-kick was deflected off Sam Hatton, leaving Joe Woolley in the home goal helpless as the ball flew into the top corner.
Other results: Basingstoke 0 Dorchester 0, Bath City 0 Hampton & Richmond 1, Bognor Regis Town 2 Chelmsford 1, Bromley 2 Newport County 1, Eastleigh 1 Bishop's Stortford 1, Fisher Athletic 0 Worcester 1, Hayes & Yeading 2 St Albans 1, Maidenhead Utd 0 Team Bath 2, Weston-Super-Mare 3 Braintree Town 1.