Goals from Ibrahima Diallo and Mohammed Salisu had earlier put Saints in front following Enda Stevens' opener.

It was the first goal for the Ghanaian defender who joined the saints last season from Spanish side Real Valladolid.

Southampton needed penalties to beat Championship side Sheffield United at Bramall Lane and secure their place in the Carabao Cup fourth round.

Oriol Romeu stepped up to score the winning penalty as Ralph Hasenhuttl's side prevailed 4-2 in the shootout.

Oli McBurnie had met Ben Osborn's cross at the back post to draw United level midway through the second half.

While Hasenhuttl's side remain winless in the Premier League after five matches, they secured the biggest away win in their history by hammering League Two Newport County 8-0 to reach this stage of the League Cup.

Their trip to a Sheffield United side relegated from the top flight last term proved far trickier, however, as Hasenhuttl chose to make nine changes from Saturday's goalless draw against Manchester City.

Having gone unbeaten in four league games since coming from behind to beat Derby County in round two, Slavisa Jokanovic's side - completely changed from the weekend - made the ideal start, then recovered from the disappointment of falling behind to force penalties.

But Romeu held his nerve to send Southampton through after Fraser Forster denied Rhian Brewster and McBurnie from the spot.