Different manager, same problem for Southampton as Callum Paterson capitalised on a terrible error from Jannik Vestergaard to ensure the Ralph Hasenhuttl era got off to a false start.
Both sides shared chances in the first half, however it was Cardiff who had the better chances to take the lead.
Arguably the best chance of the half fell to Josh Murphy after Callum Paterson did terrifically well to nick a bouncing ball from Southampton centre back Jan Bednarek, before passing to Murphy leaving him bearing down on goal.
However, the Bluebirds winger was not decisive enough, eventually over-running the ball when he could have shot or squared to an unmarked - and furious - Paterson.
Southampton did hit the bar in freakish fashion after the half hour mark. An attempted headed clearance by Cardiff striker Paterson from a Southampton corner ballooned into the air, before dropping against his own bar. The blustery conditions in the Welsh capital playing a huge part in the flight of the ball.
In a rather quiet and uninspiring second half, it was unsurprising that it was a Southampton individual error which lead to the only goal of the game.
A simple back pass for Saints centre back Jannik Vestegaard bobbled way short of his goalkeeper, allowing Paterson to slot home past Alex McCarthy, despite the desperate effort of Vestergaard to stop him.
Cardiff went on to see out the victory without much trouble, as Southampton failed to muster any great chances on the Bluebirds' goal in the second half. For Southampton, there will be much to ponder, as they played well for the first five minutes, but then barely troubled Neil Etheridge's goal for the remainder of the game.
Key Talking Point
It was far from stylish, however Cardiff got another all important three points, and encouragingly a third home Premier League win in a row. A clean sheet today was vital, and they may need plenty more from their back line as they without doubt need to bring in a striker in January.
Callum Paterson worked hard and got a goal, but he definitely looks makeshift, and is not likely to score the amount of goals they will need to keep them up.
Player Ratings - Etheridge (6), Bennett (7), Bamba (8), Morrison (7), Ecuele-Manga (7), Murphy (7), Arter (7), Gunnarsson (7), Mendez-Laing (7), Patterson (7), Camarasa (6)
Substitutions - Hoilett (6), Harris (N/A), Ralls (N/A)
Star Man - Sol Bamba
Strong, fast and composed - it was a terrific performance from the 33-year-old Cardiff centre back, who looked very forceful alongside centre back partner Sean Morrison.
The Welsh side will need more performances like this from their defence in their quest for Premier League survival; especially when goals look as though they are going to be very hard to come by.
Worst Player - Victor Camarasa
The attacker, on loan from Spanish side Betis, was relatively ineffective during the game, which did not make it easy for Callum Paterson, who usually relies upon the Spaniard's creativity in the midfield.
He looked a little off the pace, with his touch especially not looking as sharp and subtle as usual.
Key Talking Point
Ralph Hassenhuttl will have been encouraged by how the Saints started the game. However you will not get many points just by playing well in the opening stages.
They did not create much, the strikers looked very isolated and confidence looks to be very low amongst his players.
Player Ratings - McCarthy (7), Vestergaard (4), Bednarek (6), Targett (5), Valery (4), Lemina (6), Romeu (6), Hojbjerg (5), Austin (6), Armstrong (5), Redmond (5)
Substitutions - Stephens (4), Gabbiadini (5), Ward-Prowse (5),
Star Man - Mario Lemina
Really not an easy decision this. No player really endeared themselves to their new coach, however it seemed as though Hasenhuttl gave Lemina the opportunity to play slightly further up the field. Whilst it was not Lemina's greatest game, he looked far more effective in this game than any other this season during Mark Hughes' reign.
Worst Player - Jannik Vestergaard
This was nailed on to be Yan Valery. The 19-year-old was subbed off at half-time after looking way out of his depth during the first half. However it was Vestergaard who lost Southampton the game, making an inexcusable mistake, which gifted Paterson the winning goal.
Cardiff will look to try to take their home form with them on the road as they travel to Vicarage Road next Saturday to face Javi Gracia's Watford.
Ralph Hasenhuttl will make his home debut in the St. Mary's dugout next Sunday, when his side take on an in-form Arsenal team. He will be hoping for a much better performance than what he saw today.