Deeping Rangers dropped to 10th place as their poor run continued.
A single strike was enough to send them to a third defeat in a row – making it six league games without a win in the last two months.
Newport Pagnell Town are hanging on in the title race and their latest success proved hard fought.
Deeping put up stern resistance at Willen Road but a 67th-minute Dom Lawless goal won the points for the Swans.
Deeping: Bircham, Flack, Smith (sub Marsden), Burton-Jones, Tinkler, Clay, Avis, Lewis, Mooney, Coupland, Bird.
Deeping will be looking for a return to winning ways with Tuesday night’s trip to relegation-threatened Wellingborough Town who are one point above the drop zone.