Gus Poyet's men will face Chelsea in the next round of the Capital One Cup after the hosts held on for a tight victory at the Stadium of Light
Gus Poyet's men, who will face Chelsea at the Stadium of Light in the next round, held on to victory after goals from Phil Bardsley and Sebastian Larsson proved enough despite a late Maya Yoshida consolation strike.
Bardsley struck just before the hour with a scrappy effort after a desperate first half, with a much-changed Southampton unable to muster any response.
Larsson netted with a fine finish in the closing stages to seal Poyet's 100 per cent home start as Sunderland boss, having also beaten local rivals Newcastle United at the Stadium of Light, with Maya Yoshida's late header counting for nothing.
Wes Brown made his first start for Sunderland since January 2012 after a lengthy injury lay-off, with goalkeeper Vito Mannone also brought in for Keiren Westwood among seven changes.
Southampton boss Mauricio Pochettino handed a first senior start to 18-year-old midfielder Harrison Reed as only striker Jay Rodriguez was retained from the weekend draw at Stoke.
One of 10 changes to the side, Tadanari Lee, went close twice in the opening five minutes, but was off-target each time.
Emanuele Giaccherini was presented with a good chance to score his second goal of the season against Southampton, having netted in August's draw, but he could only mis-hit Ondrej Celustka's cut-back out of play.
The game was devoid of tempo as the hosts dominated possession but failed to penetrate Southampton's stubborn defence. Jozy Altidore went close on 26 minutes, firing wide from 25 yards.
Gaston Ramirez, a goalscorer in Southampton's previous two League Cup outings this term, wasted the half's best chance with two minutes to play, curling over after Jack Cork's neat pass.
The second half got under way in stunning fashion as Altidore controlled a long ball perfectly into Craig Gardner's path but the midfielder's low drive was shovelled away by Kelvin Davis.
However, the former Sunderland keeper was at fault just before the hour, failing to keep hold of Altidore's header, with Bardsley pouncing to bundle the ball home, despite Jos Hooiveld's efforts on the line.
Southampton duo Calum Chambers and Gaston Ramirez each tumbled in the penalty area, but saw appeals for a spot-kick waved away by referee Lee Mason.
Home hearts were in mouths with 15 minutes to go as Mannone smashed a clearance into substitute Adam Lallana, but looked on in relief as the ball bobbled just wide.
And the win was sealed with four minutes of normal time to play as Altidore teed up substitute Larsson and he fired low across Davis.
Yoshida sent nerves trembling just two minutes later, heading home after Hooiveld nodded a free-kick across goal, but it was not enough for Pochettino's side.