Morgan Schneiderlin scored twice as Southampton came from behind to beat West Ham United 3-1 at the Boleyn Ground.
Mark Noble put the Hammers ahead in the first half but a Schneiderlin double followed by a Graziano Pelle strike gave Ronald Koeman his first Premier League win as Saints manager.
West Ham entered the game looking to bounce back from a midweek Capital One Cup defeat to Sheffield United but on the back of an impressive 3-1 win at Crystal Palace last weekend.
Sam Allardyce named an unchanged team from Selhurst Park while Koeman handed a full debut to Shane Long after their goalless draw against West Bromwich Albion.
Both teams enjoyed plenty of possession in the first half but lacked the invention to create chances.
West Ham, who earned plaudits for their attacking brand of football against Palace, occasionally reverted to route one football with Carlton Cole the target up front.
The first chance fell to Ricardo Vaz Te after Stewart Downing’s free-kick deflected off the wall but the Hammers winger was denied by the legs of Fraser Forster.
Noble fired the hosts in front when his long-range strike took a wicked deflection off Maya Yoshida and nestled in the bottom corner. The Hammers were on top momentarily but Saints responded before half time.
After Pelle saw a header cleared off the line by Aaron Cresswell, Schneiderlin found the back of the net in stoppage time after the Hammers failed to clear a free-kick.
Koeman’s half-time teamtalk worked wonders as Southampton flew out of the traps and dominated until the final whistle.
Pelle thought he had put Saints in front when he tucked in a free-kick but he was pulled back for offside in a dubious decision from the linesman.
West Ham struggled to deal with set-pieces all afternoon and Schneiderlin made them pay again after 68 minutes when he latched on to James Ward-Prowse’s corner at the near post and flicked the ball in.
Pelle put the result beyond doubt with seven minutes left when Adrian’s save from Nathaniel Clyne’s shot fell straight to the Italian striker to fire into an empty net for his first Premier League goal.
West Ham summer signing Enner Valencia failed to make an impact after coming on as a late substitute and the hosts were booed off at the final whistle.
It was a disappointing end to a day which started with promise before kick-off when the Hammers unveiled new signing Alex Song on a season-long loan deal from Barcelona.