With ten minutes to go this match was finely balanced at 0-0, with Fleet looking the stronger side and most likely to score.
Then disaster struck for Fleet as visitors, Burgess Hill were awarded a penalty when front-man, Nick Sullivan was brought down in the box by Fleet defender, Lee Blakely. Mid-fielder, Steve Harper converted the spot-kick and Fleet were reduced to 10 men as Blakely was ordered off the field by referee, Tim Ingram.
In a matter of moments the course of the game had changed and Fleet then conceded two further goals, as they tried in vain to get back in the game.
After last week's fine win at Fisher, the penalty decision and loss of Blakely was a cruel blow to Mick Catlin's side, which had held a strong Burgess Hill side for the first 80 minutes and were trying hard to find the winner.
But this defeat, their 8th consecutive home league defeat, leaves Fleet still firmly stuck to the bottom of the table, now three points adrift of next side, Rothwell Town, and clearly with plenty to do from their final 12 matches.
Catlin was able to name a strong side at the start of the game, although missing was new signing, Tommy McCormack who failed a late fitness test.
Currently seventh in the table, the visitors were without their regular back four, who were all suspended, and keeper, Pat Gannon who was out injured.
Stand-in keeper Paul Stack, on loan from Eastbourne was tested early on and was fortunate to stay on the pitch after handling outside his area, when under pressure from Fleet striker, Eddie Smith.
Even managing to avoid a yellow card for the offence, the keeper was tested several more times in the first half, as Fleet gradually got on top of the game. Their best chance game just before the break when mid-fielder, Craig Anstey went close with a powerful strike from 15 yards out.
After the break Fleet continued to impress. Striker, Craig Leworthy went close after one slick passing move down the left. Wingman, Shaun Hale then went close with a header from a corner. Fleet continued to press for the opener, with Smith just missing, again following a corner.
For their part, the visitors looked dangerous on the break, and striker, Darren Smith should have done better in the 76th minute, after a fast break and pass by Sullivan.
Even after being reduced to ten men, Fleet continued to press but with gaps at the back, left themselves more susceptible to the fast counter-attack. From just such an opening, Sullivan scored again for the visitors in the 84th minute, running round the depleted Fleet defence.
Smith then had a chance to make amends for his earlier miss, firing in from a narrow angle with just two minutes of the match remaining.
Fleet Town: Sparshatt, Sullivan, Millerick, Hare, Blakely, Saunders, Black, (sub, Scammell, 83 mins), Anstey, Smith, Leworthy, (White, 87), Hale. Subs (not used): May, Buckland, Boyle