Southampton moved to within a point of Premier League safety after beating fellow strugglers Leicester City and increasing the pressure on their manager Brendan Rodgers.
Carlos Alcaraz gave Southampton the lead after 35 minutes, firing an effort past Leicester keeper Danny Ward.
Three minutes earlier, Ward had saved Saints captain James Ward-Prowse's penalty after Timothy Castagne blocked a cross with his arm in the area.
Leicester's Harry Souttar should have levelled the match in injury time but could only head the ball against the crossbar after Southampton keeper Gavin Bazunu was beaten by a James Maddison cross.
Southampton's victory was just their second at home in the league this season and moved them off the foot of the table into 19th, one point behind 17th-placed Leeds and a position of safety.
Leicester could have gone as high as 12th with a win, but instead remain 15th, three points clear of the drop zone.
Saints boss Ruben Selles later said: "It has been a very disappointing week but we got there at the end of the game today.
"They worked hard and showed togetherness. It wasn't the best game of football but we managed the key moments and we can celebrate a victory at St Mary's, which I haven't done since August.
"It's very important to us as we try to stay in the Premier League.
"I told them before the game I was proud of how they handled the disappointment from midweek.
"I have been proud of the work they've done in training over the last few days.
"We knew we needed Carlos Alcaraz higher up the pitch. We wanted to have space to play in behind the centre-back. It's a fantastic finish from him.
"It looks like he suffered an injury in the celebration. It's the first goal we scored in open play in the Premier League for a long time. He didn't play recently from the start in the league and he wanted to show what he can do.
"We need to do some tests and analyse his injury."
On whether they can stay up, he added: "We have six points from our last three games and we have been competitive. I think we are alive, I think we are working well and I don't think we are worse than any team in the Premier League so we are going to go for it.
"Our target is to continue fighting. If we keep showing the spirit we did today then we can achieve what we want.
"They are a great group of boys and we need to believe that they can do it."