Shane Long scored the winning goal on his 50th Premier League appearance for Southampton, who extended their unbeaten run to six matches with a hard-fought 1-0 victory at Swansea City.
Long had missed a handful of chances, but finally beat Lukasz Fabianski with a header after 69 minutes, with the visiting defence holding firm for a sixth consecutive clean sheet.
Southampton had a goal disallowed early in the second half for a foul on goalkeeper Fabianski, with Oriol Romeu having previously missed a good chance for the visitors.
Both teams came into the game in good form, with Swansea unbeaten in their last four matches, but Francesco Guidolin suffered his first loss since taking over as Swansea's new head coach in January.
A fifth win in six games takes Southampton into top-five contention after Manchester United's loss at Sunderland.
Swansea named the same side from last weekend's 1-1 draw with Crystal Palace, while Ronald Koeman made four changes. James Ward-Prowse and Steven Davis were among those reintroduced and Victor Wanyama dropped out, serving the first game of a five-match suspension.
The visitors had the first chance when the ball fell to Graziano Pelle after a period of head tennis, but Fabianski comfortably saved the Italy international's 20-yard volley.
Andre Ayew then tested Fraser Forster after nine minutes, but the Southampton goalkeeper was equal to it, before Virgil van Dijk headed Ward-Prowse's free-kick wide at the back post.
Gylfi Sigurdsson had scored five goals in his last six Premier League appearances and he shot well off target after beating Jordy Clasie in the 23rd minute, with the Iceland international later volleying over the crossbar at the end of Swansea's best move of the first half.
In the final minute before the interval Long headed Davis' cross straight at Fabianski, the striker passing up the clearest opportunity of the opening 45 minutes.
Romeu could have scored the first goal five minutes into the second half, but could only flick an excellent Ryan Bertrand cross wide of the far post.
Southampton had the ball in the net after 57 minutes, but the goal was disallowed. Fabianski dropped a cross under pressure from Jose Fonte, with Pelle turning the ball in, but referee Jon Moss ruled that the goalkeeper had been fouled.
Fabianski then saved Long's shot on the turn from 20 yards as Southampton pressed for a winning goal and the stalemate was finally broken with 21 minutes remaining.
Crosses had caused problems for Swansea all game and when Ward-Prowse whipped in another terrific centre, Long rose highest to nod home.
The hosts felt they should have had a penalty with two minutes to go when Alberto Paloschi went down in the box, but Moss was not interested, while Fabianski turned a deflected shot from substitute Charlie Austin over the crossbar as Swansea were left just three points above the drop zone.