South Park advanced to a lucrative Emirates FA Cup second qualifying round tie at Maidstone United on Saturday after a comfortable 3-1 win at Leatherhead.
The energetic Sparks took a two-goal lead inside the first half hour with fine finishes from Karl Parker and Dale Burgess.
Daniel Burnett-Williams pulled a goal back for Tanners with 10 minutes remaining, only for Burgess to seal a dramatic late win with a 90th minute third goal for the visitors.
Tanners boss Richard Brady had to do without the services of left back Adam Green (injured) and newly signed centre-back Dean Pooley (cup-tied).
But Brady’s Ryman Premier team produced yet another disjointed display as they stretched their winless run to seven matches.
Football: FA Cup defeat exposes deeper problems at Leatherhead says Brady
South Park opened the scoring on 17 minutes. James McElligott sent a deep cross into Leatherhead’s penalty area from the right and an advancing Parker was well placed to bury it at the far post.
Tanners failed to respond, and much worse was to follow as the Sparks doubled their lead on the half hour mark.
Burgess won possession at half-way and with Leatherhead looking to the referee’s assistant for an offside flag, the unchallenged forward took the ball all the way to the edge of the penalty area before beating Tanners keeper Louis Wells from 18 yards.
Leatherhead stepped up a gear in the second half in an attempt to find a way back into the tie.
South Park custodian James Wastell received his first real test on 49 minutes, denying Kiernan Hughes-Mason with two fine saves in quick succession.
Tanners pressed forward with the Sparks prepared to defend ever-deeper inside their own half.
Leatherhead’s Phil Walsh and Vas Karagiannis fired shots wide before Hughes-Mason forced another good save from Wastell.
Tanners made the vital break-through with a goal on 80 minutes - Stacy Long struck a fierce low shot from 25 yards which zipped back off the base of the post into the path of Burnett-Williams for a simple tap in.
South Park centre-back Dylan Merchant remonstrated with the referee in vociferous terms and was shown a straight red card.
With 10 minutes of the tie remaining - and with a one-man advantage - Tanners pressed forward in a desperate effort to get a late equaliser.
Walsh fired over from the edge of the box before Karagiannis flicked a close range effort just wide on 85 minutes.
With so many players in the visitors' half, Tanners left themselves exposed to a counter-attack.
On 89 minutes the Sparks played a long ball forward down the right channel.
Kofi Quartey picked out Burgess in the six yard box who beat Wells to complete a remarkable victory for the visitors.
Reaction to follow.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here