Second half goals from Maya Yoshida and Graziano Pellè secured Saints’ progress into the quarter-finals of the Capital One Cup at the expense of Aston Villa.
After a drab and goalless first half, the hosts were much improved in the second 45 minutes and struck goals that managerless Villa seemingly had no answer to.
Maya Yoshida’s first goal since last December put Saints ahead on 51 minutes when he produced a striker’s finish to find the bottom corner of Brad Guzan’s net.
The club’s top scorer, Pellè wrapped up the win 13 minutes from time when he emphatically finished off a cross from substitute Dušan Tadić, which meant Scott Sinclair's stoppage-time penalty was a mere consolation as Saints reached the last eight of this competition for the second season running.
Without the suspended Sadio Mané and injured duo of Shane Long and Jay Rodriguez, manager Ronald Koeman made seven changes from the team that started the draw at Anfield.
Gastón Ramírez, Steven Caulker, Juanmi, Maya Yoshida, Matt Targett, James Ward-Prowse and Oriol Romeu all came into the side, with Victor Wanyama captaining the team for the first time as José Fonte dropped to the bench.
Visitors Villa - in all yellow - got the game under way in front of a sold out St Mary’s and despite their lowly league position, made a competitive start to the contest.
Rudy Gestede headed wide from Ashley Westwood’s cross, before a Carlos Sanchez delivery into the area was met by Leandro Bacuna who nodded the ball straight down the throat of Maarten Stekelenburg.
Saints in contrast, struggled to create too many clear openings, and even when they did in the first half a debatable looking offside call against Graziano Pellè thwarted a cross aimed at Juanmi, who managed to fire wide anyway.
A the other end, Bacuna drove down the right flank and cut in to see a shot saved by Stekelenburg, while Saints ended the half with their clearest chance of the game when Gastón Ramírez struck a free-kick over from 30 yards after Pellè had been fouled by Kieran Richardson.
Saints appeared re-energised from their break and started the half on the front foot with Pellè seeing his defected shot loop wide after being played through by Romeu ion the edge of the area.
On 51 minutes the hosts broke the deadlock from a surprise source. A determined run forward from Maya Yoshida at right back saw him play a neat one-two with Ramírez before the Japanese international had the confidence to take on a drilled show which flew into the bottom corner of Brad Guzan’s net.
The goal prompted a tactical reshuffle from Villa, and moments later, a well-worked move resulted in Agbonlahor testing Stekelenburg from the edge of the area, but the ‘keeper was at full stretch to tip the shot over.
Villa later withdrew Gestede in favour of Scott Sinclair to deploy a more fluid 4-3-3 formation, though this made the visitors more open, which Pellè nearly profited from when he shot over on the turn after being played through by Steven Davis.
But it only took one further chance for Saints to seal their progress into the quarter-finals of the competition. A patient build-up and assist from substitute Tadić was expertly volleyed into the bottom left corner by Pellè for 2-0 and a more comfortable end to the game for Ronald Koeman’s men.
In the four minutes of stoppage-time, Virgil van Dijk felled Jordan Ayew in the area to give the visitors a late penalty.
Scott Sinclair sent Stekelenburg the wrong way to cut the deficit in half, but it was too little, too late for the Villans, whose defeat was confirmed soon after by Keith Stroud's final whistle.
Southampton team: Maarten Stekelenburg, Maya Yoshida, Steven Caulker, Virgil van Dijk, Matt Targett, Victor Wanyama (c), Oriol Romeu, Juanmi (Dušan Tadić 68), James Ward-Prowse, Gastón Ramírez (Steven Davis 68), Graziano Pellè. Unused substitutes: Kelvin Davis (GK), Jordy Clasie, José Fonte, Cuco Martina, Ryan Seager
Goals: Yoshida (51), Pellè (77)
Aston Villa team: Brad Guzan, Ciaran Clark, Jordan Amavi (Jack Grealish 63), José Ángel Crespo, Alan Hutton, Leandro Bacuna (Jordan Ayew 63), Kieran Richardson, Ashley Westwood, Carlos Sánchez, Gabriel Agbonlahor (c), Rudy Gestede (Scott Sinclair 72). Unused substitutes: Mark Bunn (GK), Jores Okore, Jordan Veretout, Carles Gil
Goal: Sinclair (pen 90)
Referee: Keith Stroud
Attendance: 31,314 (including 3,258 away)