Eddie Howe’s Bournemouth deservedly claimed the spoils in the south coast derby to greatly aid their bid for survival.
The Cherries picked off a lacklustre Southampton side with goals in either half from Steve Cook and Benik Afobe to give them just their fourth home league win of the season.
With other results around the country going in their favour, Bournemouth now find themselves eight points clear of the danger zone after this vital win.
The home side started strongly, forcing a succession of early corners as they pinned Saints back.
Ronald Koeman will be left wondering how different the game might have turned out had Charlie Austin made the most of Southampton’s first meaningful attack.
Cedric Soares pulled a low cross back from the right hand side but Austin could only power a first-time shot wide of the post.
Sadio Mane hooked a shot over midway through the half as the visitors briefly threatened to come out of their shell.
Matt Ritchie made the first of two decisive contributions as Bournemouth got their noses in front on 31 minutes.
The Scotland international saw his teasing free-kick palmed away by Fraser Forster but Cook acrobatically sent it back into the Southampton net from six yards out.
Harry Arter darted at the Southampton rearguard as half time approached but his shot was deflected wide off Virgil van Dijk. From the corner, Bournemouth had a half-hearted penalty appeal waved away by Mike Dean as the ball came off Shane Long.
Arter and Long were forced off for either side in the second half and it was the latter’s replacement – Graziano Pelle – that came closest to levelling.
He struck a powerful low shot from 25 yards out that flew just the wrong side of Artur Boruc’s upright with 17 minutes remaining.
The nerves were beginning to jangle amongst the home faithful as the clock ticked down and they got the relief of a second goal 11 minutes from full time.
Ritchie this time delivered a pin-point set piece from the right wing and Afobe ghosted across his maker to glance a header into the net past Forster.
It capped a memorable night at the Vitality Stadium and leaves Howe and Bournemouth in a strong position to retain their top flight status this season.