James Ward-Prowse and Jan Valery fired Southampton, who wiped away a sluggish start, to a 2-1 comeback win against Tottenham.
Southampton had looked largely outmatched when Harry Kane scored his 200th career goal, extending a run of five in seven games, on 26 minutes.
Spurs appeared set to press on with Christian Eriksen coming close to doubling the advantage with a pair of chances. The first crashed against the bar, before Angus Gunn fought off a heavy attempt.
A double-change at the break changed Southampton’s fortunes, with Shane Long teeing up Nathan Redmond only for the midfielder to hit the side netting.
Long would last just 15 minutes before departing through injury that will be a cause of concern with Danny Ings sidelined and teenager Michael Obafemi out for the rest of the season.
But the Southampton revival continued when Valery scored for the second game in a row. He tallied a spectacular goal in a 3-2 defeat at Manchester United and matched the effort thumping a bouncing shot past Hugo Lloris.
Ward-Prowse, who has become a fixture in the side since Ralph Hasenhuttl’s appointment having scored six times in nine league games, then edged Southampton ahead with another tremendous display from a dead-ball situation.
Lloris was no match for the 24-year-old’s shot that curled past him from the edge of the box to jubilation and mounting anxiety inside St Mary’s.
Southampton, however, held on for a crucial victory that moved them up to 16th in the table with two points separating them and relegation threatened Cardiff City.
Southampton: Gunn, Bertrand, Vestergaard, Yoshida, Bednarek, Valery, Hojbjerg, Romeu (Long 46 (Armstrong 73), Redmond, Ward-Prowse, Austin (Sims 46).
Unused subs: McCarthy (GK), Stephens, Targett, Slattery.
Goals: Valery (76), Ward-Prowse (81).
Bookings: Romeu (10), Valery (22), Hojbjerg (78), Redmond (88).
Tottenham: Lloris, Rose (Davies 82), Vertonghen, Sanchez, Walker, Dier, Eriksen, Sissoko, Ali (Llorente 82), Kane, Moura (Son 72).
Unused subs: Gazzaniga (GK), Foyth, Wanyama, Lamela.
Goals: Kane (26).
Bookings: Walker (79), Sissoko (88).