Pagham lost for only the second time in the league this season as Hassocks did the double at The Beacon.
Their hopes came unstuck as early as the second minute when veteran Phil Gault slotted home. James Westlake soon doubled the lead.
Neil Murfin gave the visitors hope with a goal ten minutes before half-time.
But Sam Jeremiah scored with eight minutes left to send the Lions home pointless and with Rye having knocked them off the top.
Chichester remained rooted to the bottom of division one after two goals in each half by East Grinstead condemned them to a 4-1 home defeat.
At Nyetimber Lane, Pagham reserves enjoyed a 3-2 win over Hassocks’ seconds thanks to Michael Frangou’s double and a Ryan Champion winner.