After saving two penalties in the 3-0 defeat to Aston Villa, Southampton goalkeeper Aaron Ramsdale was required to make a near-post save to thwart Niclas Füllkrug in the early stages at the London Stadium.
While Füllkrug went close to scoring in back-to-back home games, it was relegated Southampton who offered the greater attacking threat in the first period.
Defender Kyle Walker-Peters steered a right-foot shot just wide of Alphonse Areola’s far post, shortly before Kamaldeen Sulemana rattled the crossbar after he pounced onto Lucas Paquetá’s weak clearance.
The Saints were ultimately made to rue those missed opportunities when the hosts produced an incisive counter-attack to take the lead within the opening two minutes of the restart. West Ham’s talisman Jarrod Bowen applied the finishing touches to the swift move, cutting inside onto his favoured left foot before guiding home his ninth league goal of the season.
The Hammers briefly thought they had found a second when Ramsdale knocked the ball into his own net under pressure from Füllkrug, only for the referee to penalise the striker for a foul on the Southampton goalkeeper.
With the deficit still a slender one, the Saints threatened to pull level through defender Jack Stephens, whose driven effort forced Areola to make a strong save down low to his right. Tyler Dibling then blazed over a gilt-edged opportunity as the visitors continued to search for an equaliser.
They looked set to experience disappointment in their quest for an equaliser until Ugochukwu produced a clinical strike in the 93rd minute.
The Chelsea loanee lashed a first-time shot past Areola after the ball looped into his path from Walker-Peters’s deflected strike, helping his team equal the worst-ever PL points tally with five games left to collect at least one more point.
Flashscore Man of the Match: Lesley Ugochukwu (Southampton)