The 0-2 loss to Fulham capped a nightmarish season for Southampton entrenched at the bottom of the table.
Second half goals from Carlos Vinicius and Aleksandar Mitrovic condemned Southampton to fall in front of their own fans at St Mary’s.
Ruben Selles’ side are winless in their last 11 games and their dip in the league has been confirmed with two games to go.
The Saints will return to the second tier for the first time in 11 years.
Southampton have spent most of the season in the bottom three and Selles could not save them from falling after replacing the sacked Nathan Jones in February.
Jones had lasted just 14 games as the successor to Ralph Hasenhuttl, who was sacked in November after four years in charge.
The warning signs were there for a while for Southampton, who finished a modest 15th in the previous two seasons and suffered a 9-0 thrashing at Manchester United in February 2021.
(With contributions from AFP)