After the win at Rye United, another would have consolidated Selsey’s top-half spot, but Lingfield hit five past them to secure three points which helps them stay clear of the bottom three.
The visitors took a commanding three-goal lead into half-time thanks to Dean Roye (two) and Aaron Courtney.
After Daryl Coleman scored a fourth just after the break Selsey seemed doomed, but they did mount a mini-comeback.
Calum Britton struck on 53 minutes and Max Thoms made a return to the scoresheet late on, only for leading scorer Josh Coulson to come off the bench and kill off any potential comeback.
Selsey slip to 13th, but can still look up the table with four games to go and safety virtually guaranteed.
Selsey now need only two points to be mathematically safe.
But with four teams between them and the bottom three, relegation is not a pressing concern for Selsey.
Boss Ian Martin will be hoping for a better showing at home to Three Bridges on Saturday, with the away side in decent form and preparing for their cup-final appearance at the end of the month.