Three second-half goals from Southampton condemned Norwich to their fourth defeat in five games, denting their hopes of Premier League survival.
Saints top scorer Danny Ings curled in the opener shortly after half-time, before Stuart Armstrong doubled their lead five minutes later.
Norwich looked lacklustre at an eerily empty Carrow Road, and Nathan Redmond confirmed a win for Southampton against his old club when he slotted into the bottom right corner late on.
The Canaries remain bottom of the table following a 104-day absence.
And the time away from Premier League action, due to the coronavirus pandemic, did little to spark any signs of a comeback from Norwich, who have just eight games to claw back a six-point deficit on 17th-placed Watford above the relegation zone.
In the Premier League era, no team with 21 points or fewer after their 30th game of a season has survived the drop.
It was a positive performance from Southampton, who capitalised on the break, pressing high and taking advantage of space in behind the Canaries’ defence.
The Saints move up into 13th place, and have opened up a 10-point gap on the bottom three, having played a game more than those hovering around the safety mark.
