Boss Ronald Koeman admits Southampton must rebuild their waning confidence as they try to cling on to their European dream.
The Saints have won just once in their last five Barclays Premier League games and have failed to score in their last three outings after Saturday's 1-0 defeat at West Brom.
They remain fifth in the table, but Liverpool will go above them on Sunday if they beat Manchester City.
Southampton host Crystal Palace on Tuesday and Koeman insists they have to improve.
"The whole team's form is down on earlier this season. There's a little less confidence than we had, but the best thing for confidence is to win and next Tuesday is important," he said.
"I was always realistic. I never thought we'd qualify for the Champions League because a lot of big teams normally fight for that in the table.
"We have to fight for more points than Southampton did last season. We'll play our way and see what happens.
"We have to accept it and keep going. Every game is a difficult one and every team is fighting to win. The problem is going a goal down, it's more difficult."
Saido Berahino scored after just 70 seconds to win the game and Koeman was forced to make a tactical change, taking off defender Florin Gardos for winger Eljero Elia after just 25 minutes.
But the boss had no regrets over his line-up, despite the slow start which cost them the game.
"If I had to do the line-up again I'd do same. This season we've played two or three times out of this system and won every game," he said.
"The players know the system and we have the players to do it, but at 1-0 down we always had three defenders against one attacker and being 1-0 down made it a different game."
Berahino scored his 17th goal of the season with a rasping half-volley from the edge of the box, but limped off in the second half with a foot injury.
He, along with Brown Ideye, is a doubt for Tuesday's derby at Aston Villa, but, after being injured at Sunderland last week, head coach Tony Pulis praised the match-winner.
"It's a wonderful strike, a wonderful goal, there's no questioning his talent. He's a top-class talent and over the past couple of weeks he has really bought into what we're trying to do," said Pulis.
"He works so hard and his attitude has been very good. He's played with an injection in his foot, he's not trained all week. He's the icing on the cake, that extra bit of quality."
The Baggies moved up to 13th and are eight points clear of the bottom three after the win and Pulis was intrigued by the tactical battle with the Saints.
"They changed the shape of their team and we didn't realise that until an hour before the game," he said.
"So we changed ours a little bit, instead of having James Morrison and (Craig) Gardner wider, we brought them in a little bit to what as effectively a diamond and they did the job brilliantly.
"I was really disappointed Southampton changed their shape back, when they did they caused us more problems."