A second-half winner by Callum Paterson earned a precious victory for Cardiff City and brought defeat for Ralph Hasenhuttl in his first match in charge of Southampton.
There were chances for both sides in an evenly-matched encounter at Cardiff City Stadium with Josh Murphy going close for the hosts in the first half and Charlie Austin narrowly shooting wide for the visitors.
After the break Paterson, on his 50th appearance for Cardiff, pounced on Jan Vestergaard's mishit backpass to break the deadlock on 74 minutes.
Southampton pressed for an equaliser and Manolo Gabbiadini missed a late opportunity as Neil Warnock’s men held on to take three points.
Cardiff climb two places in the table to 14th on 14 points. Southampton drop one place to 19th on nine.
See: Cardiff report | Southampton report
Next fixtures
Cardiff City: 15 Dec v Watford (A)
Southampton: 16 Dec v Arsenal (H)
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