Southampton have secured their place in the quarter-finals of the League Cup with a 1-0 win over Premier League strugglers Sunderland at St Mary's.

Sofiane Boufal scored the game's only goal in the second half to extend the hosts' unbeaten run and dump more misery on Black Cats boss David Moyes, who ended the evening in the stands for reacting angrily when his side were denied a penalty.

The visitors took the game to their opponents, testing Saints goalkeeper Alex McCarthy for the first time in the 22nd minute when Wahbi Khazri's shot was saved in the bottom corner.

Southampton, who named five academy graduates in their starting XI, were content to defend deep in the first half, restricting Sunderland to long-range efforts but creating little in the final third.

The game remained cagey early in the second period, but came to life after the hour when the Saints' record signing Boufal turned his marker in the box and curled a strike into the top corner to fire the hosts in front.

Sunderland had the chance to draw level in the 76th minute as substitute Jermain Defoe gained possession in the box and let fly, forcing another save out of McCarthy with the visitors' last meaningful goal attempt of the night.

Things went from bad to worse for Moyes in the 90th minute when he was sent to the stands for an outburst in response to Victor Anichebe being denied a late penalty after going down in the area.

Play resumed with four minutes of uneventful stoppage time before the full-time whistle was greeted with rapturous applause from the home supporters at St Mary's.