The Eagles saw their 2022/23 FA Cup campaign conclude after goals from James Ward-Prowse and Adam Armstrong cancelled out Odsonne Edouard’s early opener.
“The game looked a bit like the game against Tottenham,” Vieira said at his post-match press conference.
“We had some really good periods during the game, managed to score the first goal and had the opportunities to hurt them a little bit more. We didn’t take our chances.
“With the quality they have on set-pieces, they managed to score a goal, we lost a bit of momentum, they scored the goal in second-half – and we are out of the competition.
“Today we created opportunities and chances, but when you don’t score, you leave yourself open. Southampton worked hard to get the win, and congratulations to them.”
Vieira reiterated that he and his coaching staff will continue to strive to develop their players’ mentality in this regard.
“I see that at times we can play some really good football and create chances,” he noted. “The mindset has to be better, but to be better, we have to work on that.
“That will not happen in the next weeks or months, it’s a process that will take time. It’s up to me and the staff to show that taking chances is important in winning the game.
“Maturity is important. Experience is important. The work we are doing every day is important and me, the manager, and the staff are being more demanding on the players.
“If we keep demanding from the players, week after week, they will be where we want them to be.”