Sunderland's EFL Cup run is over after a wondergoal from Southampton record signing Sofiane Boufal.
The £16million summer signing struck a stunning goal in the 66th minute to send the Saints through at the expense of Sunderland.
The first half of the fourth round clash was a dire affair but it sparked into life in the second half. Sunderland had chances to equalise, sub Jermain Defoe's effort saved by Alex McCarthy.
The Black Cats had a late appeal for a penalty turned down, Victor Anichebe brought down under pressure from Maya Yoshida but it was waved away to the fury of David Moyes.
Moyes was sent to the stands for his protests as Sunderland were knocked out of the EFL Cup.
Moyes made four changes from the side beaten 1-0 at the London Stadium, with Steven Pienaar, John O'Shea, Javier Manquillo and Jermain Defoe all rested and on the bench.
The Saints, meanwhile, made nine changes to the team that drew 1-1 with Manchester City, with boss Claude Puel naming five academy graduates in the team.
There was also a first start for club record signing Sofiane Boufal, the 23-year-old attacking midfielder signed from Lille in the summer for £16million.
Summer signing Paddy McNair started on the left-side of midfield for Sunderland, after previously playing centre-back, central midfield and in an attacking midfield role.
The hosts had the first opening five minutes in, Pierre-Emile Hojbjerg's low drive well blocked by skipper for the night Lamine Kone, although Jordan Pickford looked to have it covered.
There was a slight break in play shortly afterwards, Billy Jones involved in a clash of heads with Jay Rodriguez - the striker later subbed for 19-year-old Olufela Olomola.
It was a poor opening 45 minutes, with Sunderland camped inside their own half for the first 15 minutes.
Wahbi Khazri, playing in the number 10 role, forced Alex McCarthy into a low save 23 minutes in but the offside had already gone up, wrongly as it turned out.
Khazri then missed the ball completely on the edge of the penalty area after Patrick van Aanholt had picked him out. A poor miss. He also blasted one 25-yard effort high over the bar.
Sunderland had contained the early pressure well against a youthful Saints side and began to see more of the ball. Gifting possession away was the main problem.
Duncan Watmore and Khazri the biggest culprits.
The hosts offered little threat either, in truth, with Jordan Pickford not forced into making a save in the first half. Hojbjerg and sub Olomola both firing over the crossbar.
Half-time: Southampton 0 Sunderland 0
Sunderland, with the full backing of the 1,500-strong travelling support, started the second half with more intent. Djilobodji with a superb diagonal pass to van Aanholt.
The Dutch left-back miscontrolled, though and the danger passed. Anichebe was starved of service on his first start but he earned a free-kick 55 minutes in.
Van Aanholt's effort was too high and sailed over McCarthy's crossbar. Pickford looked uncomfortable on two Ward-Prowse corners, missing the first and flapping at the second.
Watmore sliced wide from a volley on the hour mark as the game threatened to burst into life.
It did six minutes later but it was Saints summer signing Boufal that got the breakthrough with a stunning strike.
He trapped a high ball forward, before cutting inside from the left-hand side of the penalty area and curling a superb effort into Pickford's top right-hand corner.
McNair, who had been quiet, saw a header at the far post blocked as Sunderland threatened to hit back straight away.
Moyes turned to Defoe from the subs bench to spark some life into Sunderland, Khazri making way. And he almost levelled in the 75th minute.
His low effort from a tight angle pushed behind by McCarthy. Anichebe had a late strong shout for a penalty denied, after being pulled down by Yoshida.
It was waved away though, Moyes was furious and he was sent off for his protests in added-on time.
Sunderland's hopes of making it through to the quarter-finals of the competition dashed.
Full-time: Southampton 1 Sunderland 0
Southampton (4-2-3-1): McCarthy, Yoshida, Fonte (C), Reed (Clasie, 82), McQueen, Hojbjerg, Stephens, Isgrove (Redmond, 72), Boufal, Ward-Prowse, Rodriguez (Olomola, 26)
Subs Not Used: Lewis, Austin, Martina, Van Dijk.
Booked: Olomola (61)
Goals: Boufal (66)
Sunderland AFC (4-2-3-1): Pickford, Jones, Djilobodji, Kone (C), van Aanholt, McNair (Pienaar, 87), Rodwell, Ndong, Khazri (Defoe, 72), Watmore (Gooch, 87), Anichebe.
Subs Not Used: Mika, O'Shea, Manquillo, Love.
Booked: Jones (64), Ndong (90)
Referee: Christopher Kavanagh (Lancashire)