Jack McInerney scored his second match winner in as many weeks on Saturday as the Philadelphia Union posted a 1-0 win over the New England Revolution at PPL Park.
Sloppy conditions all afternoon made it difficult for either side to generate any offensive chances over the first 45 minutes.
But the Union had the upper hand in the second half and spent much of the time in the attacking third.
McInerney's breakthrough came in the 76th minute as Sebastien Le Toux lofted a corner kick into the box, allowing McInerney to get a clean header away on goal.
New England goalkeeper Bobby Shuttleworth made a spectacular first save, but left a rebound and McInerney made no mistake from in close to give Philadelphia the lead.
New England had a handful of excellent opportunities down the stretch, including a golden chance in second-half stoppage time when Honduras international Jerry Bengtson collected a ball just outside the box and ripped a quick shot on the turn, but it sailed over Zac MacMath's net and Philadelphia captured three vital points at home.
Philadelphia remains unbeaten against New England in eight all-time meetings, holding a 5-0-3 record against their rivals to the north.