Sidley's superb end-of-season run has guaranteed their County League first division status with a game to go.
The Blues made it four wins out of five to haul themselves clear of danger when Steve Morris struck a 90th-minute winner against Arundel on Saturday with a half-volley from the edge of the box.
Sidley's joint-manger Andy Laskey said: "We had a few dodgy results at Easter and if someone had said then that we'd be safe with a game left I wouldn't have believed them."
The last remaining relegation place will be filled by either East Grinstead, Southwick or Worthing United who could still need a point from their final match after losing 1-0 at Rye and Iden United.
Glyn White's last home game in charge of Rye was settled by Phil Rhodes' close-range finish with ten minutes left.
Last year's champions Chichester secured their top-flight status by winning 3-0 at Redhill thanks to goals from Mark Jackson, John Price and Roger Moore.
In Division Three, once-proud Haywards Heath face Mid Sussex League football next season after a goalless draw in their last game at Forest meant they went down.
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