Alan Pardew believes Saints are starting to create a 'winning mentality' after notching a seventh success in eight games.
The manager praised that fine record, but conceded that there is still something that he is not quite happy with.
"That's what it's all about, a winning attitude and a winning mentality," he said after knocking Charlton out of the Johnstone's Paint Trophy.
"We're in the dressing room again, we've won and that's what you want to do every week.
"I'm just disappointed with the last ten minutes. We conceded a goal and we want to get a clean sheet.
"It's really eating into us at the minute. Maybe because we're putting so much focus on that, it's making us nervous and it cost us a goal.
"There was some good play tonight. Although we were a little bit sloppy, there was still some good stuff and that's what we want.
"We want to be assertive and go on to the next game."
The assurance running throughout the side was evident in much of Saints' forward play even though Pardew had made one or two changes to his team, including the decision to give midfielder Dean Hammond the captain's armband for the evening.
"We've got good players and they're confident at the moment, you can see that," he highlighted.
"Dean Hammond was outstanding tonight I thought. He played the captain's role and I thought he was the best player on the pitch and that bodes well.
"He does so much work unnoticed. He's not the prettiest of footballers, but he's effective at what he does and that was important tonight."
The gaffer was also pleased for defender Wayne Thomas, who sent out the perfect message to his manager that he is not prepared to lose his place in the side, by netting the opening goal of the game.
"He's had a tough run with injuries, so it was nice for him to score a goal for all the hard work he's put in.
"I've got a nice problem for Sunday, and someone will be disappointed, but it's nicer to be left out when you're winning than when you're losing.
"I think we've played a lot better than that. But it's a good performance and we go to Brighton now and are looking forward to that.
"We've got two home games coming up, and we want to win them both."
