Claude Puel is hoping his side can continue their good work as they go in search of a third straight home win in a week against Crystal Palace.
Victory over Sparta Praha in the UEFA Europa League was followed up by a first Premier League success against Swansea City, with Charlie Austin on target.
And confidence is high going into the EFL Cup clash against their league counterparts at St Mary's.
He told Southampton's official YouTube channel: “It gave us confidence to get a second win of the week but I think we can do better by being more efficient.
“We had many chances (against Swansea) and it’s important to score more but it's positive because we played with different players. We kept our identity and played good football which is interesting for the future.
“You’ve got to prepare for the cup because it is important for the squad."