Hampstead, previous leaders on goal difference, dropped points in a 2- 2 draw at Paddington to Cup giant-killers High Wycombe.
After Nigel Land had twice given the Middlesex club the lead, Wycombe fought back with goals from Andy Burroughs and Rob Cheatle. Wycombe, having been reduced at one stage to nine men following temporary suspensions, scored the equaliser with four minutes remaining.
Chichester, with goals from Andrew Savory, Brian Lock, Gregg Watson and Danny Jaeger, beat Beckenham 4-2 to slip into third place. Beckenham's goals came from David Knox and David Penfold.
The much-awaited First Division clash between Purley and Old Cranleighans ended in a convincing 5-0 win for Purley. Paddy Osborn, who was the first player to 150 National League goals while with Reading earlier in the season, scored twice with a brace also from Doug Bolger and the fifth from P J Weller.
Old Cranleighans' Welsh internationals, David Knapp and Jon Rees, were unable to respond although there was perhaps some excuse for their third international, Don Williams, whose wife, Gail, gave birth to their first child a few hours earlier.Reuse content