CHALFONT stretched their unbeaten league run to six games but a goalless draw at Leverstock saw their lead at the top of the table cut to five points.
The Saints have only failed to hit the back of the net in three other league games this season but never threatened a breakthrough in Hertfordshire.
Shots on target were rare for both sides as a uncharacteristically blunt Chalfont side laboured.
It was only when substitute Ryan Welsh came on with 24 minutes to go that the Saints began to threaten and only an offside flag stopped Charlie Strutton continue his scoring streak when he converted a Welsh centre.
Second-placed Tring took full advantage with a 4-1 win at Hertford ahead of the two sides clashing at Mill Meadow on Saturday.
SAINTS: Oliver, Cumber, Louth, Walsh, Jeffery, Hicks, Lewis, Stack (Long 71), Strutton, Hughes, Ajayi (Welsh 66).
Subs (not used): Carroll, Williams.