Two goals from Southampton's Romeo Lavia and Adam Armstrong (scored in the 28th and 46th minutes respectively) were enough to see off a spirited Chelsea who could only manage a goal from Raheen Sterling's 23rd strike.
The win saw Southampton climb to the 7th spot on the English premier league table. Chelsea on the other hand fell to the 8th spot on the same table.
Chelsea have started this season on a decline and it will be interesting to see how they perform in subsequent games