Nigel Pearson believes Saints can go unbeaten until the end of the season to secure their Championship status.
Saints travel to play-off chasing Charlton tomorrow before a home game against Burnley, a trip to table-topping West Brom and a final day St Mary's clash with Sheffield United.
Pearson's side travel to The Valley in good spirits after last weekend's 2-0 win over promotion chasing Bristol City.
And while the Saints boss won't get too carried away, he believes it is not just hot air to believe the team can go unbeaten in the next four games.
He said: "I'd like to think we can go unbeaten now.
"I'm optimistic anyway but we're capable of doing that.
"It's not false optimism, we're capable of it. But ultimately we have to go and perform, it's as simple as that.
"This will be a tough game, as will all the remaining fixtures.
"You can spend a lot of energy on presuming that things are going to go one way or another and speculating on how other teams are going to do and that's a waste of time.
"We ultimately have to look after our next performance."
Charlton need the win to try and boost their chances of making the play-offs - despite only winning five of their last 21 league games - and could have been given a wake up call by Saints' result last week.
However, Pearson isn't thinking that way.
Instead, he is trying to keep his side focussed on what they have to do.
"I don't know what they're thinking and I'm not going to," he said.
"What interests me is our team and how we approach it.
"I know that if we go about it the right way, we've got a good chance of getting the right result - whether that be a win or a draw.
"We've got a good chance if we reproduce the same sort of performance."
Full story, and more Charlton v Saints previews, in today's Daily Echo.
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