Charlie Austin came off the bench to score the winner as Southampton beat Swansea City 1-0 at St Mary's.
Nathan Redmond wasted two great opportunities to give the Saints the lead in the first half, but it was the second-half introduction of Austin that proved the difference.
The striker, who had scored a brace against Sparta Prague in the Europa League in midweek, went agonisingly close to opening the scoring when his header crashed back off the crossbar and drifted the wrong side of the post off the back of goalkeeper Lukasz Fabianski.
But Austin made no mistake with his second great chance in the 64th minute, controlling a deflected Redmond cross on his chest before lashing in what turned out to be a deserved winning goal.
The win - Southampton's first of the season - was the least that Claude Puel's side deserved after a completely dominant display against their lacklustre visitors.
They had the pick of the opportunities in a goalless first half, playing some superb football at times, with Dusan Tadic, Redmond and Shane Long linking up to great effect in the final third.
An error by Swansea goalkeeper Fabianski, spilling Long's shot from range, went unpunished as Tadic was caught offside as he attempted to turn home the rebound. However, the goalkeeper did make amends as he tipped a Tadic free-kick over the bar shortly afterwards, and a Virgil van Dijk header also forced a save out of the busy Swansea keeper as Southampton continued to push for an opener as the first half progressed.
The Saints stepped it up a gear as the interval approached, and the St Mary's faithful thought they had a penalty when Long went down in the box, only for referee Mike Jones to instead book the striker for diving - a decision that split opinion, despite the striker going down before contact was made.
But the opening goal should have come from the boot of Redmond moments before the break, only for the winger to blast over the bar when clean through - a miss that further frustrated Long, who was unmarked and waiting for a square ball in the centre of the box.
Redmond produced an even more shocking miss in the 44th minute, cutting back on to his right foot to wrong-foot the last covering defender and leave the goal gaping, only to once again send his shot soaring into the crowd behind the goal.
A frustrated Saints came exploding out of the blocks in the second half, with the lively Long sending a shot sliding past Fabianski only for Kyle Naughton to clear it off the line. And Long should have had a goal to his name shortly afterwards when he tucked home Redmond's cross, only for the winger to be wrongly adjudged as having drifted offside.
Frustration started to build around St Mary's as Austin's header came back off the bar, but the goal finally came just after the hour mark and Swansea barely threatened from there on, with a Fraser Forster save from Gylfi Sigurdsson's shot the only late scare for the home side.
Player ratings
Southampton: Forster (7), Cedric (6), Fonte (7), van Dijk (7), Bertrand (7), Clasie (6), Romeu (6), Tadic (8), Davis (7), Redmond (7), Long (8)
Subs used: Austin (7), Hojbjerg (6), Martina (6)
Swansea: Fabianski (5), Naughton (6), Fernandez (5), Kingsley (5), Amat (6), Fer (6), Cork (5), Ki (6), Sigurdsson (7), Llorente (7), Barrow (6),
Subs used: Rangel (6), Montero (6), Borja Baston (6),
Man of the match: Dusan Tadic