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.
74 - GOAL!!! @Callump7!!! (1-0)
— Cardiff City FC (@CardiffCityFC) December 8, 2018
Matchday Live https://t.co/ONo6wwMoja#CARSOU #CityAsOne ⚽️⚽️ pic.twitter.com/ltQVzm8u6A
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.
Cardiff City
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.
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.
Source: 90min