Dan Smith's late header earned Bognor their EIGHTH successive win.
They looked like they would have to settle for a point after stalwart striker Barry Hayles had made it 1-1 for Merstham with nine minutes left on a cold, grey afternoon at Nyewood Lane.
That came after Tommy Leigh had scrambled in a first-half opener for the in-form Rocks and it was left to Smith to head in what proved the winner.
The Rocks are eighth in the Isthmian premier table, just three points off the play-off zone - that having been in the bottom three in mid-September.
FA Cup headline-makers Chichester City drew 1-1 with Sittingbourne at Oaklands Park, skipper Connor Cody earning the point by cancelling out Thomas Fagg's strike for the Kent visitors.
Pagham and Midhurst were without games in the SCFL but Selsey earned a sensational 4-3 win at Storrington with Max Davies scoring all four - the last two coming in injury time.
In division two Bosham were hammered 8-1 at Littlehampton Utd with only a Joel Jackson penalty to show for their efforts.
In local rugby, Chichester's excellent home form in London one south continued - just. They beat Dartfordians 27-26. Bognor won 39-8 away to Eastleigh twos in the Hampshire premier.
West Sussex's Jess Breach help England's Red Roses to a 17-15 victory over France in Exeter - their second win against the French this month.