Southampton won for the second consecutive week to keep Huddersfield Town in the relegation zone after a fifth straight defeat.
Ralph Hasenhuttl’s side were 2-0 up at the break thanks to Nathan Redmond’s cool strike and a Danny Ings penalty.
The hosts improved after the break and halved the deficit through Philip Billing’s swerving, long-range effort.
But 18-year-old substitute Michael Obafemi’s first Premier League goal sealed the win for the Saints.
On the back of Southampton’s first back-to-back wins since April 2017, the south coast side move one place up the table into 16th place.
Huddersfield, with just four goals scored at home so far this season, remain in 19th place and are without injured top scorer Aaron Mooy until February.