Brighton & Hove Albion added to relegation-threatened Southampton's woes with a 4-0 win at the St Mary's Stadium on Saturday, handing the Saints their eighth consecutive home defeat in the Premier League.
Southampton remain rooted to the bottom of the table with just nine points from 26 matches, while Brighton move up to eighth with 40 and are four points behind fourth-placed Manchester City, who have a game in hand.
Brazilian Joao Pedro fired the visitors into the lead in the 23rd minute after a one-two with fellow forward Georginio Rutter, chipping the ball over Southampton goalkeeper Aaron Ramsdale from 15 metres out.
Before opening the scoring, Brighton had already sent out warning signs with defensive midfielder Carlos Baleba coming close and Japanese winger Kaoru Mitoma wasting a huge chance when he sent his shot wide.
Frenchman Rutter looked lively throughout and was rewarded for his efforts when he doubled Brighton's lead in the 56th minute by tapping in Yankuba Minteh's square pass.
Mitoma dinked over Ramsdale to make it 3-0 and 19-year-old midfielder Jack Hinshelwood added another goal from the centre to complete the rout after Southampton failed to clear a set-piece.
Cameron Archer had the ball in the back of the net minutes after the break but the Southampton forward's celebrations were cut short when the assistant referee's flag went up for offside.
The scoreline would have looked a lot worse for Southampton if not for Ramsdale, who pulled off a series of fine saves in the second half to deny efforts from Minteh and Baleba. Brighton had 12 shots on target to Southampton's one.
"We out-worked them, out-sprinted them and were very aggressive. That was the key to winning this game," Brighton head coach Fabian Huerzeler told the club's website.
"You can't expect to win 4-0 but we defended compactly and won a lot of second duels. The only regret is that we didn't score (more) goals – Ramsdale was outstanding and made several good saves.
"They had a five-man defence and played very much man to man. So we had to find good relationships on the pitch and the players did it that well. All the players were sharp and today Joao had his chance and I think he took it."
Things get no easier for Southampton, who are still chasing a third Premier League win this season, as they brace themselves for a tough set of fixtures, starting with a trip to sixth-placed Chelsea on Tuesday, followed by a visit to leaders Liverpool on March 8.
"It's a really tough moment for us, many (defeats) in the Premier League and now we have a big game in a few days. We need to rest well and be (ready)," Southampton midfielder Mateus Fernandes told the club's website.
"It's the small things at this level. They're very important... We have quality in our squad, I think we need some confidence."