Michail Antonio was the Hammers' matchwinner for the second game running, heading in Dimitri Payet's corner after seven minutes, and the result came with an added bonus in that it denied the Lilywhites a chance to go top of the Premier League.
Slaven Bilic's team are now unbeaten in nine matches in all competitions and the manager, his players and supporters alike were understandably elated at the final whistle.
It took roughly 20 minutes for Antonio to tweet his delight, with Manuel Lanzini next to follow, before James Tomkins, Darren Randolph and Aaron Cresswell also got in on the act, along with youngster George Dobson who made the squad for the very first time.
West Ham, who've lost just one of their last 19 matches, are now only a point behind the two Manchester clubs, with fifth-placed United still to play in the Premier League.
The Hammers also face top-four sides Arsenal and Leicester City before the season is out.