Norwich's survival hopes received a major blow as Southampton took a giant stride towards safety thanks to Danny Ings, Stuart Armstrong and Nathan Redmond strikes.
With Daniel Farke's six points adrift and fast running out of time, the rock-bottom Canaries desperately needed to make a winning return to Premier League action after a 104-day break due to the coronavirus pandemic.
But a fine Norwich start quickly petered out as Southampton moved 10 points clear of the drop zone, with second-half goals from Ings, Armstrong and Redmond sealing a 3-0 win at an empty Carrow Road.
Republic of Ireland international Michael Obafemi started for Southampton and played 82 minutes while U-21 Adam Idah came off the bench for the final 10 minutes for the Canaries.
Shane Long missed out with a back complaint but Southampton manager Ralph Hasenhuettl said the Tipperary native should be fit to face Arsenal next week.
Saints waltzed to victory in East Anglia but things could have been so different had Ings not been alert in his own box during the opening minutes to close down Tom Trybull.
Ralph Hasenhuttl, who signed a new deal until 2024 earlier in the month, would see his side dominate the match after a shaky start, with Ings hitting the crossbar in the first half.
Saints turned their dominance into goals shortly after half-time, with the England hopeful scoring a fine curling effort before setting up Armstrong to bury a low shot past Tim Krul.
Redmond added a third against former club Norwich, whose uphill battle to avoid an immediate return to the Championship now has an even steeper incline.
As at Wednesday's Premier League matches, both sides took a knee as part of the Black Lives Matter movement after observing a minute's silence for those impacted by Covid-19.