Terry Brown had put out a mixed side for the tie which saw Nick Crittenden partner the returning Gearing up front. Hassan Sulaiman played on the right wing, while former Rushden & Diamonds midfielder Sean Ridgway also started.
Brown's system paid off almost straight away when Ridgway's shot was parried by Fleet keeper Paul Smith and Gearing headed home the rebound.
Gearing headed over the bar and Ahmed Deen forced a good save fromSmith as the Shots piled forward, but Fleet were never out of the running as James Field, on loan from the Shots, blasted over and Eddie Smith was denied by Dan Weait in the Shots goal.
Within seconds of the restart, however, it became obvious that the game could not continue as dense fog rolled into the Recreation Ground, and on 46 minutes after speaking to both managers, referee Tim Ingram decided to call off the game.
“I asked the referee to give it another five minutes but he couldn't see his linesman,” Brown explained.
“Fair play to Fleet who came down, worked very hard and it didn't look like there were two divisions between us. They could have scored and there was nothing to choose between the sides.
“I'd have like to get the match done and dusted before the FA Cup and I'd have loved to see Roscoe D'Sane out there for half an hour, but that didn't look very likely today. The ref made the right decision.”
SHOTS: Weait, Somner, Jinadu, Winfield, Hamilton (sub Parker, 45mins), Sulaiman, Ridgway, Scott, Deen, Crittenden, Gearing. Not used: Shepherd, Breen. Illsey, D'Sane.
FLEET: Smith; Mann, Salmon, Lewis, Noakes, George, Field, Davies, Girling, Smith, Lennon. Not used: Bonsu, Dickens, Diak John, Panter, Gray.
The attendance from the abandoned match has been confirmed as 494.